Make RISC-V testing reliable

[sxa]

This is a bit of a background task at the moment but the RISC-V testing (currently limited to sanity.openjdk) typically fails due to hitting the 10 hours timeout for the test. I have been experimenting with runnign PARALLEL=Dynamic which seems to help lead it to finish. Having said that, the most recent set of runs look like they may have finished underneath the 10 hour limit.

Relevant jobs:

• https://ci.adoptopenjdk.net/job/Test_openjdk19_hs_sanity.openjdk_riscv64_linux/
• https://ci.adoptopenjdk.net/view/Test_openjdk/job/Test_openjdk11_j9_sanity.openjdk_riscv64_linux/ (Competes, but 24/27 targets are skipped)
• https://ci.adoptopenjdk.net/view/Test_openjdk/job/Test_openjdk11_bisheng_sanity.openjdk_riscv64_linux/ (Hits 10 hour limit)

[sxa]

I've removed ci.role.test from test-sxa-debian11-riscv64-1 as it has an older glibc than the PLCT machines and therefore will not successfully run the tests.