compiler/intrinsics/sha/cli/TestUseMD5IntrinsicsOptionOnUnsupportedCPU.java fails on riscv64

[Grinder](https://ci.adoptium.net/job/Grinder/parambuild/?SDK_RESOURCE=upstream&TARGET=hotspot_custom&TEST_FLAG=&UPSTREAM_TEST_JOB_NAME=Test_openjdk21_hs_extended.openjdk_riscv64_linux&DOCKER_REQUIRED=false&ACTIVE_NODE_TIMEOUT=5&VENDOR_TEST_DIRS=&EXTRA_DOCKER_ARGS=&TKG_OWNER_BRANCH=adoptium%3Amaster&OPENJ9_SYSTEMTEST_OWNER_BRANCH=eclipse%3Amaster&PLATFORM=riscv64_linux&GENERATE_JOBS=true&KEEP_REPORTDIR=true&PERSONAL_BUILD=false&ADOPTOPENJDK_REPO=https%3A%2F%2Fgithub.com%2Fadoptium%2Faqa-tests.git&RERUN_ITERATIONS=0&LABEL=&EXTRA_OPTIONS=&CUSTOMIZED_SDK_URL=&BUILD_IDENTIFIER=&ADOPTOPENJDK_BRANCH=v1.0.13-release&LIGHT_WEIGHT_CHECKOUT=false&NON_AQA_TEST_REPOS=&USE_JRE=false&ARTIFACTORY_SERVER=&KEEP_WORKSPACE=false&USER_CREDENTIALS_ID=&JDK_VERSION=21&ITERATIONS=1&VENDOR_TEST_REPOS=&JDK_REPO=https%3A%2F%2Fgithub.com%2Fadoptium%2Fjdk21u&OPENJ9_BRANCH=master&OPENJ9_SHA=&JCK_GIT_REPO=&VENDOR_TEST_BRANCHES=&OPENJ9_REPO=https%3A%2F%2Fgithub.com%2Feclipse-openj9%2Fopenj9.git&UPSTREAM_JOB_NAME=build-scripts%2Fjobs%2Frelease%2Fjobs%2Fjdk21u%2Fjdk21u-release-linux-riscv64-temurin&CLOUD_PROVIDER=&PLATFORM_AND_MACHINE=&CUSTOM_TARGET=compiler%2Fintrinsics%2Fsha%2Fcli%2FTestUseMD5IntrinsicsOptionOnUnsupportedCPU.java&VENDOR_TEST_SHAS=&JDK_BRANCH=jdk-21.0.11%2B9_adopt&TEST_IMAGES_REQUIRED=true&LABEL_ADDITION=&ARTIFACTORY_REPO=&ARTIFACTORY_ROOT_DIR=&UPSTREAM_TEST_JOB_NUMBER=150&DOCKERIMAGE_TAG=&JDK_IMPL=hotspot&TEST_TIME=&SSH_AGENT_CREDENTIAL=&AUTO_DETECT=true&SLACK_CHANNEL=aqavit-bot&DYNAMIC_COMPILE=false&ADOPTOPENJDK_SYSTEMTEST_OWNER_BRANCH=adoptium%3Amaster&APPLICATION_OPTIONS=&CUSTOMIZED_SDK_URL_CREDENTIAL_ID=eclipse_temurin_bot_email_and_token&ARCHIVE_TEST_RESULTS=false&OPENJDK_SHA=&NUM_MACHINES=&RERUN_FAILURE=false&BUILD_LIST=openjdk&USE_TESTENV_PROPERTIES=true&UPSTREAM_JOB_NUMBER=23&STF_OWNER_BRANCH=adoptium%3Amaster&TIME_LIMIT=25&JVM_OPTIONS=&PARALLEL=None)
```
16:50:00 STDOUT:
16:50:00 CPU arch riscv64 does not match aarch64.*
16:50:00 CPU arch riscv64 does not match amd64.*
16:50:00 CPU arch riscv64 does not match i386.*
16:50:00 CPU arch riscv64 does not match x86.*
16:50:00 Running compiler.intrinsics.sha.cli.testcases.GenericTestCaseForUnsupportedCPU
16:50:00 java.lang.AssertionError: Option 'UseMD5Intrinsics' is expected to have 'false' value, but is 'UseMD5Intrinsics = t'.
16:50:00 Option 'UseMD5Intrinsics' should be disabled by default
16:50:00 at jdk.test.lib.cli.CommandLineOptionTest.verifyOptionValue(CommandLineOptionTest.java:310)
16:50:00 at jdk.test.lib.cli.CommandLineOptionTest.verifyOptionValue(CommandLineOptionTest.java:280)
16:50:00 at jdk.test.lib.cli.CommandLineOptionTest.verifyOptionValueForSameVM(CommandLineOptionTest.java:407)
16:50:00 at compiler.intrinsics.sha.cli.testcases.GenericTestCaseForUnsupportedCPU.verifyOptionValues(GenericTestCaseForUnsupportedCPU.java:89)
16:50:00 at compiler.intrinsics.sha.cli.DigestOptionsBase$TestCase.test(DigestOptionsBase.java:163)
16:50:00 at compiler.intrinsics.sha.cli.DigestOptionsBase.runTestCases(DigestOptionsBase.java:139)
16:50:00 at jdk.test.lib.cli.CommandLineOptionTest.test(CommandLineOptionTest.java:540)
16:50:00 at compiler.intrinsics.sha.cli.TestUseMD5IntrinsicsOptionOnUnsupportedCPU.main(TestUseMD5IntrinsicsOptionOnUnsupportedCPU.java:46)
16:50:00 at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
16:50:00 at java.base/java.lang.reflect.Method.invoke(Method.java:580)
16:50:00 at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
16:50:00 at java.base/java.lang.Thread.run(Thread.java:1583)
16:50:00 Caused by: java.lang.RuntimeException: 'UseMD5Intrinsics\s*:?=\s*false' missing from stdout/stderr
16:50:00 at jdk.test.lib.process.OutputAnalyzer.shouldMatch(OutputAnalyzer.java:371)
16:50:00 at jdk.test.lib.cli.CommandLineOptionTest.verifyOptionValue(CommandLineOptionTest.java:299)
16:50:00 ... 11 more
16:50:00
16:50:00 JavaTest Message: Test threw exception: java.lang.AssertionError: Option 'UseMD5Intrinsics' is expected to have 'false' value, but is 'UseMD5Intrinsics = t'.
16:50:00 Option 'UseMD5Intrinsics' should be disabled by default
16:50:00 JavaTest Message: shutting down test
16:50:00
16:50:00 STATUS:Failed.`main' threw exception: java.lang.AssertionError: Option 'UseMD5Intrinsics' is expected to have 'false' value, but is 'UseMD5Intrinsics = t'. Option 'UseMD5Intrinsics' should be disabled by default
```

Assisted-by: copilot

**April 2026 failure** ([#7008 comment](https://github.com/adoptium/aqa-tests/issues/7008#issuecomment-4253374708)):
- Job: [Test_openjdk21_hs_extended.openjdk_riscv64_linux_testList_6 #45](https://ci.adoptium.net/job/Test_openjdk21_hs_extended.openjdk_riscv64_linux_testList_6/45/) — `hotspot_compiler_0` — passed: 1,490; **failed: 1**
- Grinder rerun: [#16978](https://ci.adoptium.net/job/Grinder/16978/) — ⚠️ UNSTABLE
- Root cause: `AssertionError: Option 'UseMD5Intrinsics' is expected to have 'false' value` — test expects the intrinsic to be disabled by default, but it appears enabled on riscv64

**Historical failures (same test, recurring)**:
- **October 2025 JDK-21 triage** ([#6686](https://github.com/adoptium/aqa-tests/issues/6686#issuecomment-3434292882)): passed: 2,145; failed: 1 — Grinder [#15131](https://ci.adoptium.net/job/Grinder/15131/) — FAILS. Note: *"Newly refactored testcase in jdk-21.0.9 under [JDK-8345471](https://bugs.openjdk.org/browse/JDK-8345471). Not sure working correctly on riscv, so needs upstream porter bug to be raised — non-blocking."*
- **October 2025 JDK-17 triage** ([#6687](https://github.com/adoptium/aqa-tests/issues/6687)): same failure, same note
- **January 2026 JDK-21 dry-run** ([#6824](https://github.com/adoptium/aqa-tests/issues/6824#issuecomment-3769883259)): `hotspot_compiler_0` — passed: 1,488; failed: 2 (including this test)

This is a consistent failure across at least 3 release cycles. The test verifies `UseMD5Intrinsics` is `false` on unsupported CPUs, but riscv64 appears to report the option as enabled (possibly a mis-classification introduced by [JDK-8345471](https://bugs.openjdk.org/browse/JDK-8345471) which refactored the intrinsics in JDK 21.0.9).

Start with compiler/intrinsics/sha/cli/TestUseMD5IntrinsicsOptionOnUnsupportedCPU.java and the supporting DigestOptionsBase and GenericTestCaseForUnsupportedCPU classes. Reproduce the riscv64 failure from the linked Grinder job, then review the JDK-8345471 refactoring and the option's CPU classification. Done means the test's unsupported-CPU expectation is correct on riscv64 and the relevant test passes.

Written by the indexing model from the issue text.