Although #5098 merged successfully, recently the PR system has been persistently failing in an x86 Clang configuration of std :: tests/Dev11_1086953_call_once_overhaul:39. This looks like:

name: std.tests/Dev11_1086953_call_once_overhaul
output: OSError(22, 'Operation did not complete successfully because the file contains a virus or potentially unwanted software', None, 225, None) at C:\a\_work\1\s\tests\utils\stl\test\format.py:231

This is a false positive (which appears to only repro on our Server 2025 VMs; it doesn't repro on my local Win11 machine), which I suppose we could report to the relevant team at great effort. We could also just skip building this particular test for Clang x86.

However, reverting #5098 entirely appears to work robustly. Since I wasn't eager to mess with this in the first place, I think a revert is appropriate.

This preserves a comment improvement and adjusts other comments.