jemalloc: use GCC intrinsics for unwinding in profiling

[teskje]

This is a workaround for deadlocks caused by nested unwinding. Alternative to #32139.

Motivation

• This PR fixes a recognized bug.

Fixes https://github.com/MaterializeInc/database-issues/issues/9159

Tips for reviewer

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[def-]

We can do a bunch of anyhow! calls to have a quick stress test to see if this prevents the issues. (or revert #32138)

[teskje]

I assume all the segfaults in CI come from us not enforcing frame pointers. We could enforce them with force-frame-pointers, but we'd also have to do so for all libraries we depend on and apparently we risk segfaults if we miss one. The libunwind approach feels safer, if we can get it to work.