gh-123295: Update TSAN suppression comment and sample for set_default_allocator_unlocked #123391

Job	Run time
Change detection / Compute changed files	12s
Check if generated files are up to date	5m 12s
Windows MSI${{ '' }}	0s
Docs	0s
Address sanitizer	7m 27s
Ubuntu SSL tests with OpenSSL (1.1.1w)	2m 10s
CIFuzz	0s
Ubuntu SSL tests with OpenSSL (3.0.13)	2m 13s
Hypothesis tests on Ubuntu	5m 29s
Ubuntu SSL tests with OpenSSL (3.1.5)	2m 8s
Ubuntu SSL tests with OpenSSL (3.2.1)	2m 5s
Thread sanitizer / Thread sanitizer	4m 22s
WASI / build and test	6m 0s
Thread sanitizer (free-threading) / Thread sanitizer	7m 10s
Windows / build (arm64)	2m 58s
Windows (free-threading) / build (arm64)	2m 31s
Windows / build and test (Win32)	14m 48s
Windows (free-threading) / build and test (Win32)	23m 2s
Windows / build and test (x64)	14m 31s
Windows (free-threading) / build and test (x64)	21m 3s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 24s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	4m 44s
macOS / build and test (macos-13)	9m 35s
Ubuntu / build and test	7m 28s
Ubuntu (free-threading) / build and test	9m 23s
All required checks pass	1s
	2h 39m 56s

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