[ci] Use AlmaLinux 10 for ARM build

[guitargeek]

This is to test the newer GCC 14 on ARM.

Should also add coverage for #14446.

Two commits with fixes to h2root and RVec tests are also added to avoid these test failures on alma10 ARM without any further changes:

TEST FAILURES:
317:gtest-math-vecops-vecops-rvec
1998:roottest-root-hist-h2root

[github-actions]

Test Results

    21 files      21 suites   3d 22h 8m 30s ⏱️
 3 778 tests  3 777 ✅ 0 💤 1 ❌
77 472 runs  77 471 ✅ 0 💤 1 ❌

For more details on these failures, see this check.

Results for commit 16c3d8b.

♻️ This comment has been updated with latest results.

[pcanal]

What do the experiment use for arm64? i.e. shouldn't we still test both alma9 and alma10.

[guitargeek]

I don't know, but I would prefer to not blow up the CI matrix too much for no reason. If you want, we can also keep Alma 9. In the end, the motivation for this PR was to demo that aarch64 works with gcc 14, which is shipped with Alma 10. If I can show that, #14446 can be closed.

In any case, if the fixes to h2root and the RVec tests successfully fix the problems with Alma 10 ARM, I will open independent PRs for these fixes.

[pcanal]

@dpiparo What coverage do we need for arm64/alma?