Rebase selftests/rseq to v6.0

Gavin Shanrequested to merge
(removed):bug2107034 into main

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2107034
Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=49263850
Upstream Status: v6.0 and RHEL-only to enable kvm/selftests/rseq_test
Tested: Passed selftests/rseq and kvm/selftests/rseq_test

This series rebases selftests/rseq to v6.0 so that it's compatible with
glibc-2.35. RHEL9.2 has glibc-2.34, plus features backported from glibc-2.35.
With glibc-2.35 supported by selftests/rseq, kvm/selftests/rseq_test can
be enabled in the last RHEL-only patch.

Note that there are two relevant bugs: bug2107034 and bug2116492. The former
depends on the later one. The plan is to post only one MR for them, which
is associated with bug2107034. It means bug2116492 becomes 'Test-Only'
after the MR is merged.

Changelog:
v2:
Improved cover letter to explain the relationship between bug2107034
and bug2116492 (Connie)
Dropped 3 Risc-V related commits (Connie/Eric)

Signed-off-by: Gavin Shan gshan@redhat.com

Edited by Gavin Shan

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