gh-116738: Make _json module safe in the free-threading build #122733

Job	Run time
Change detection / Compute changed files	9s
Check if generated files are up to date	5m 6s
Ubuntu SSL tests with OpenSSL (1.1.1w)	2m 14s
Windows MSI${{ '' }}	0s
Ubuntu SSL tests with OpenSSL (3.0.13)	1m 58s
Ubuntu SSL tests with OpenSSL (3.1.5)	2m 2s
Ubuntu SSL tests with OpenSSL (3.2.1)	1m 59s
Address sanitizer	9m 29s
CIFuzz (address)	20m 2s
Hypothesis tests on Ubuntu	5m 40s
CIFuzz (undefined)	20m 47s
CIFuzz (memory)	20m 30s
Thread sanitizer / Thread sanitizer	4m 27s
Thread sanitizer (free-threading) / Thread sanitizer	7m 25s
WASI / build and test	6m 8s
Windows / build (arm64)	3m 14s
Windows (free-threading) / build (arm64)	3m 5s
Windows / build and test (Win32)	15m 55s
Windows (free-threading) / build and test (Win32)	23m 57s
Windows / build and test (x64)	16m 5s
Windows (free-threading) / build and test (x64)	22m 47s
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 36s
macOS / build and test (macos-13)	9m 51s
Ubuntu (free-threading) / build and test	10m 6s
Ubuntu / build and test	7m 42s
Docs / Docs	2m 1s
Docs / Docs (Oldest Sphinx)	1m 55s
Docs / Doctest	16m 54s
All required checks pass	4s
	4h 12m 21s

Provide feedback