ASAN reports 'stack-use-after-scope' at seemingly random places after switching to clang-15

[itrofimow]

running benchmarks: https://pastebin.com/raw/HQickcfU
running unittests: https://pastebin.com/raw/t1D05a9M

I'm pretty certain this is ASAN wrongdoings, leaving this issue here for reference mostly

[Anton3]

This makes ASAN-testing userver unusable under clang-15, we should turn off ASAN in the false-positive function calls.

[itrofimow]

The thing is there is no "false-positive function calls" - shadow memory gets poisoned somewhere before swapcontext call and gets accessed somewhere after the call, and that booms.

However disabling stack-use-after-scope detection in asan fixes this; not great not terrible.

[itrofimow]

Retesting this once again with clang-15, fails reliably (although with different errors) somewhere in libbacktrace: https://pastebin.com/raw/fbVc2WkE

With this patch applied to clang-15.0.7 no errors are reported (actually asan reports about some direct leak in one allocation, but it's definitely unrelated)

[itrofimow]

Seems to be fixed in clang 16.0.2