vm/cc/Fail2 flaky turned Fail on vm-linux-release-riscv64-qemu

[aam]

Failing build

--- Command "run_vm_unittest" (took 181ms):
DART_CONFIGURATION=ReleaseXRISCV64 qemu-riscv64 -L /usr/riscv64-linux-gnu/ out/ReleaseXRISCV64/run_vm_tests --dfe=/b/s/w/ir/cache/builder/sdk/out/ReleaseXRISCV64/gen/kernel_service.dill --sound-null-safety --ignore-unrecognized-flags Fail2

exit code:
255

stdout:
Running test: Fail2
Done: Fail2

stderr:
../../runtime/vm/assert_test.cc: 55: error: This test fails with two arguments: -100, 42

--- Re-run this test:
python3 tools/test.py -n vm-linux-release-riscv64-qemu vm/cc/Fail2

[aam]

at present it fails on all bots, not clear what was the other outcome on qemu-riscv64 that made the test flaky on that platform

[a-siva]

//cc @rmacnak-google

[aam]

The other outcome seems to be 'Crash' from this log

/=======================================================================================\
| vm-linux-release-riscv64-qemu:vm/cc/Fail2 failed again (Fail -> Crash, expected Pass) |
\=======================================================================================/

--- Command "run_vm_unittest" (took 159ms):
DART_CONFIGURATION=ReleaseXRISCV64 qemu-riscv64 -L /usr/riscv64-linux-gnu/ out/ReleaseXRISCV64/run_vm_tests --dfe=/b/s/w/ir/cache/builder/sdk/out/ReleaseXRISCV64/gen/kernel_service.dill --sound-null-safety --ignore-unrecognized-flags Fail2

exit code:
-11

stderr:
qemu-riscv64: QEMU internal SIGSEGV {code=MAPERR, addr=0x20}

--- Re-run this test:
python3 tools/test.py -n vm-linux-release-riscv64-qemu vm/cc/Fail2

Can't reproduce crash locally.