gh-123295: Update TSAN suppression comment and sample for set_default_allocator_unlocked #123388

Job	Run time
Change detection / Compute changed files	10s
Check if generated files are up to date	5m 0s
Address sanitizer	7m 21s
Ubuntu SSL tests with OpenSSL (1.1.1w)	1m 57s
Ubuntu SSL tests with OpenSSL (3.0.13)	1m 56s
Ubuntu SSL tests with OpenSSL (3.1.5)	2m 14s
Windows MSI${{ '' }}	0s
Ubuntu SSL tests with OpenSSL (3.2.1)	2m 1s
Docs	0s
Hypothesis tests on Ubuntu	5m 14s
CIFuzz	0s
WASI / build and test	6m 7s
Thread sanitizer / Thread sanitizer	4m 11s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 13s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 1s
Thread sanitizer (free-threading) / Thread sanitizer	7m 19s
macOS / build and test (macos-13)	10m 54s
Ubuntu / build and test	7m 20s
Ubuntu (free-threading) / build and test	9m 7s
Windows / build (arm64)	2m 2s
Windows / build and test (Win32)	10m 46s
Windows (free-threading) / build (arm64)	2m 42s
Windows (free-threading) / build and test (Win32)	10m 40s
Windows / build and test (x64)	10m 39s
Windows (free-threading) / build and test (x64)	10m 41s
All required checks pass	2s
	2h 8m 37s

Provide feedback