sbt test failed

**Type of issue**: bug report

**Impact**: no functional change | API addition (no impact on existing code) | API modification | unknown

**Development Phase**: request | proposal

**If the current behavior is a bug, please provide the steps to reproduce the problem:**
I've followed below steps and got stuck at sbt test.
```
git clone https://github.com/chipsalliance/chisel3.git
cd chisel3
sbt compile
sbt test
Got failed 1 test and log shown below:
g++ -I. -MMD -I/usr/share/verilator/include -I/usr/share/verilator/include/vltstd -DVM_COVERAGE=0 -DVM_SC=0 -DVM_TRACE=1 -faligned-new -fcf-protection=none -Wno-bool-operation -Wno-sign-compare -Wno-uninitialized -Wno-unused-but-set-variable -Wno-unused-parameter -Wno-unused-variable -Wno-shadow -Wno-undefined-bool-conversion -O1 -DTOP_TYPE=VModuleIODynamicIndexTester -DVL_USER_FINISH -include VModuleIODynamicIndexTester.h -c -o VModuleIODynamicIndexTester__ALLsup.o VModuleIODynamicIndexTester__ALLsup.cpp
ar -cr VModuleIODynamicIndexTester__ALL.a VModuleIODynamicIndexTester__ALLcls.o VModuleIODynamicIndexTester__ALLsup.o
ranlib VModuleIODynamicIndexTester__ALL.a
g++ top.o verilated.o verilated_vcd_c.o VModuleIODynamicIndexTester__ALL.a -o VModuleIODynamicIndexTester -lm -lstdc++
make: Leaving directory '/home/vijayan/CHISEL_THREE/chisel3/test_run_dir/ModuleIODynamicIndexTester/202110201626225768060872132690812'
[info] - Dynamic indexing of a Vec of Module IOs should work
[info] - It should be possible to bulk connect a Vec and a Seq
[error] Vec.scala:435: Vec and Seq being bulk connected have different lengths! in class chiselTests.VecSpec$$anon$10
[error] There were 1 error(s) during hardware elaboration.
[info] - Bulk connecting a Vec and Seq of different sizes should report a ChiselException
[info] - It should be possible to initialize a Vec with DontCare
[info] - Indexing a Chisel type Vec by a hardware type should give a sane error message
[info] Run completed in 48 minutes, 57 seconds.
[info] Total number of tests run: 955
[info] Suites: completed 149, aborted 0
[info] Tests: succeeded 954, failed 1, canceled 0, ignored 27, pending 0
[info] *** 1 TEST FAILED ***
[error] Failed tests:
[error] chiselTests.TraceSpec
[error] (Test / test) sbt.TestsFailedException: Tests unsuccessful
[error] Total time: 2943 s (49:03), completed 20-Oct-2021, 4:26:28 PM
```

**What is the current behavior?**
1 sbt test got failed and unsuccessful.

**What is the expected behavior?**
sbt test to be successful for all tests.

**Please tell us about your environment:**
OS: ubuntu 20.04

Run sbt test and inspect the failing chiselTests.TraceSpec result, including the reported Vec.scala:435 elaboration error. Done means sbt test completes with all 955 tests passing; the issue does not identify a source file or expected fix beyond that.

Written by the indexing model from the issue text.