sanity.openjdk tests FAILED because it wasn't able to find jtreg jar

**Failing Test Info**
12:49:35 FAILED test targets:
12:49:35 jdk_lang_1
12:49:35 jdk_math_0
12:49:35 jdk_security1_1
12:49:35 jdk_security2_1
12:49:35 jdk_stream_0
12:49:35 jdk11_tier1_buffer_0
12:49:35 jdk11_tier1_buffer_1
12:49:35 jdk_byte128vector_j9_0
12:49:35 jdk_long128vector_j9_0

**last passing job** https://hyc-runtimes-jenkins.swg-devops.com/job/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal/21/

**Jenkins Test Job Info**
Jenkins Test Job Name: (Example: Test_openjdk8_hs_extended.openjdk_arm_linux_testList_0)
Jenkins Test Job URL:
TRSS link for the build (if available):

**Deep History Link from TRSS (if available)**

** Rerun in Grinder Link (if available) or Steps to Reproduce**

**Java Version output (from console output)**
```
[2026-06-10T16:48:12.879Z] Run /home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java -version
[2026-06-10T16:48:12.879Z] =JAVA VERSION OUTPUT BEGIN=
[2026-06-10T16:48:13.266Z] java version "21.0.12-internal" 2026-07-21
[2026-06-10T16:48:13.266Z] IBM Semeru Runtime Certified Edition for z/OS (build 21.0.12-internal-adhoc.JENKINS.BuildJDK21s390xzosPersonal)
[2026-06-10T16:48:13.266Z] IBM J9 VM (build 21.0.12-internal-adhoc.JENKINS.BuildJDK21s390xzosPersonal-zos-off-heap-memlimit-8acdb740cfa, JRE 21 z/OS s390x-64-Bit Compressed References 20260610_3938 (JIT enabled, AOT enabled)
[2026-06-10T16:48:13.266Z] OpenJ9 - 8acdb740cfa
[2026-06-10T16:48:13.266Z] OMR - e2cdcb21ccd
[2026-06-10T16:48:13.266Z] IBM - e4abedf846e
[2026-06-10T16:48:13.266Z] JCL - 31ed07172b8 based on jdk-21.0.12+5)
```

**Relevant Console Output (showing exceptions/errors/crashes)**
```
[2026-06-10T16:49:31.915Z] ===============================================
[2026-06-10T16:49:31.915Z] Running test jdk_long128vector_j9_0 ...
[2026-06-10T16:49:31.915Z] ===============================================
[2026-06-10T16:49:31.915Z] jdk_long128vector_j9_0 Start Time: Wed Jun 10 16:49:31 2026 Epoch Time (ms): 1781110171769
[2026-06-10T16:49:31.915Z] variation: -Xjit:{*Long128VectorTests*}(count=1,enforceVectorAPIExpansion),disableAsyncCompilation,dontApplyLogFileNameSuffix,verbose={vectorAPI}
[2026-06-10T16:49:31.915Z] JVM_OPTIONS: -Xjit:{*Long128VectorTests*}(count=1,enforceVectorAPIExpansion),disableAsyncCompilation,dontApplyLogFileNameSuffix,verbose={vectorAPI} -Xverbosegclog -Dcom.ibm.tools.attach.enable=yes
[2026-06-10T16:49:31.915Z] { \
[2026-06-10T16:49:31.915Z] echo ""; echo "TEST SETUP:"; \
[2026-06-10T16:49:31.915Z] "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java" -Xshareclasses:destroyAll; "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java" -Xshareclasses:groupAccess,destroyAll; echo "cache cleanup done"; \
[2026-06-10T16:49:31.915Z] mkdir -p "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"; \
[2026-06-10T16:49:31.915Z] cd "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"; \
[2026-06-10T16:49:31.915Z] echo ""; echo "TESTING:"; \
[2026-06-10T16:49:31.915Z] "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java" -Xmx512m -jar "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../../jvmtest/openjdk/jtreg/lib/jtreg.jar" \
[2026-06-10T16:49:31.915Z] -agentvm -a -ea -esa -v:fail,error,time,nopass -retain:fail,error,*.dmp,javacore.*,heapdump.*,*.trc -ignore:quiet -timeoutFactor:2 -xml:verify -concurrency:4 -nativepath:"/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/openjdk-test-image/jdk/jtreg/native" -vmoptions:"-Xmx512m -Xjit:{*Long128VectorTests*}(count=1,enforceVectorAPIExpansion),disableAsyncCompilation,dontApplyLogFileNameSuffix,verbose={vectorAPI} -Xverbosegclog -Dcom.ibm.tools.attach.enable=yes " \
[2026-06-10T16:49:31.915Z] -timeoutHandler:jtreg.openj9.CoreDumpTimeoutHandler -timeoutHandlerDir:"/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/../../externalDependency/lib/openj9jtregtimeouthandler.jar" \
[2026-06-10T16:49:31.915Z] -w ""/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"/work" \
[2026-06-10T16:49:31.915Z] -r ""/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"/report" \
[2026-06-10T16:49:31.915Z] -jdk:"/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image" \
[2026-06-10T16:49:31.915Z] "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../openjdk/openjdk-jdk/test/jdk/jdk/incubator/vector/Long128VectorTests.java" && \
[2026-06-10T16:49:31.916Z] echo "grep #VECTOR API "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"/work/jdk/incubator/vector/Long128VectorTests.jtr" && \
[2026-06-10T16:49:31.916Z] grep "#VECTOR API" "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/jdk_long128vector_j9_0"/work/jdk/incubator/vector/Long128VectorTests.jtr; \
[2026-06-10T16:49:31.916Z] if [ $? -eq 0 ]; then echo "-----------------------------------"; echo "jdk_long128vector_j9_0""_PASSED"; echo "-----------------------------------"; cd /home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/..; else echo "-----------------------------------"; echo "jdk_long128vector_j9_0""_FAILED"; echo "-----------------------------------"; fi; \
[2026-06-10T16:49:31.916Z] echo ""; echo "TEST TEARDOWN:"; \
[2026-06-10T16:49:31.916Z] "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java" -Xshareclasses:destroyAll; "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/jdkbinary/j2sdk-image/bin/java" -Xshareclasses:groupAccess,destroyAll; echo "cache cleanup done"; \
[2026-06-10T16:49:31.916Z] } 2>&1 | tee -a "/home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../TKG/output_17811101544328/TestTargetResult";
[2026-06-10T16:49:31.916Z]
[2026-06-10T16:49:31.916Z] TEST SETUP:
[2026-06-10T16:49:32.301Z] JVMSHRC005I No shared class caches available
[2026-06-10T16:49:32.301Z] JVMSHRC005I No shared class caches available
[2026-06-10T16:49:33.617Z] cache cleanup done
[2026-06-10T16:49:33.617Z]
[2026-06-10T16:49:33.617Z] TESTING:
[2026-06-10T16:49:34.001Z] Error: Unable to access jarfile /home/jenkins/workspace/Test_openjdk21_ibm_sanity.openjdk_s390x_zos_Personal_testList_1/aqa-tests/TKG/../../jvmtest/openjdk/jtreg/lib/jtreg.jar
[2026-06-10T16:49:34.001Z] -----------------------------------
[2026-06-10T16:49:34.001Z] jdk_long128vector_j9_0_FAILED
[2026-06-10T16:49:34.001Z] -----------------------------------
```

**Attach or link to relevant artifacts**
In the case of test failures, the Jenkins Test Job has test_output.tar.gz artifacts that contain extra logs and core files in the case of crashes. Please download and inspect these files. Copy relevant files to an accessible location that can be linked to, or attach relevant files to this issue directly.

Start by comparing the failing Jenkins job output with the linked last passing job, focusing on the jtreg path ../../jvmtest/openjdk/jtreg/lib/jtreg.jar. Inspect test_output.tar.gz and the listed failing targets, including jdk_long128vector_j9_0, to determine why the jar is absent or misplaced. Done means the sanity.openjdk targets can launch jtreg and complete successfully.

Written by the indexing model from the issue text.