RWMutex hangs on Linux riscv64

[babsingh]

https://ci.eclipse.org/omr/job/PullRequest-linux_riscv64_cross/857/console

11:23:11  20: [----------] 18 tests from RWMutex
13:05:04  Cancelling nested steps due to timeout
13:05:04  Sending interrupt signal to process
13:05:24  After 20s process did not stop

This failure has been noticed in the following PR builds:

• Fix build breaks with gcc 11.3.1 #6702; and
• Fix bci in loop strider IV widening and re-enable #277 (comment).

[babsingh]

@janvrany FYI

[janvrany]

@babsingh

I just re-enabled OMR jobs on my personal CI and current master run just fine on both x86_64 host cross-compiled and on real RISC-V HW (unleashed).

Jobs are set up so they monitor master and report any failure. I'll keep them enabled for some time to see whether I'll get run into similar issues. Right now, I have not idea what has happened.

Same for #6704 & #6665.