Support instrumenting the STL with ASan

[CaseyCarter]

Add support for instrumenting the STL with ASan by setting the STL_ASAN_BUILD cmake option and enable this support in the STL-ASan-CI pipeline. This lets us run "full ASan" tests with coverage of the header-only code and binary libraries. For now that requires client programs to be ASan instrumented since they statically link with either the entire STL (/MT or /MTd) or the contents of the import library (/MD or /MDd).

This includes a fairly icky workaround for an initialization ordering bug (VSO-1913897) which injects a dynamically-initialized thread_local into each test TU. It's a matter of opinion whether it's more horrible to have ASan and non-ASan test coverage diverge by using this workaround only for ASan testing, or more horrible to have the ASan workaround affect non-ASan testing. I've chosen to use the workaround universally. This should truly be temporary since there's ongoing work to fix the issue with a coordinated change in the compiler and ASan runtime.

Drive-by: increase paranoia around google/sanitizers#328. This change isn't strictly needed but would have saved me some time and confusion.

⚠️ Requires coordinated changes in the internal test infrastructure ⚠️

.. to add tests/std/include to the include path for the libc++ test suite to support the VSO-1913897 workaround.

[CaseyCarter]

STL-ASan-CI validation: https://dev.azure.com/vclibs/STL/_build/results?buildId=15919&view=results

[StephanTLavavej]

LGTM. I pushed a conflict-free merge with main, plus the comment cleanup you noted, plus a TRANSITION comment that I wanted.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

I had to push a commit because /clr and /clr:pure hate thread_local:

/clr error:

D:\a01\_work\5\s\src\vctools\crt\github\tests\std\include\vso1913897.hpp(11): error C2482: '__stl_asan_init_variable': dynamic initialization of thread local data not allowed in managed code

/clr:pure errors:

D:\a01\_work\5\s\src\vctools\crt\github\tests\std\include\vso1913897.hpp(11): error C3403: thread_local cannot be used with /clr:pure or /clr:safe
D:\a01\_work\5\s\src\vctools\crt\github\tests\std\include\vso1913897.hpp(11): error C2482: '__stl_asan_init_variable': dynamic initialization of thread local data not allowed in managed code

[StephanTLavavej]

Thanks for this major ASan achievement! 🧗 ⛰️ 😻