gh-125825: add `subgroup()` and `split()` methods on `BaseException` #130171

Job	Run time
Change detection / Compute changed files	10s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.0.15)	2m 16s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.1.7)	2m 8s
Address sanitizer	3m 47s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.2.3)	2m 11s
Check if Autoconf files are up to date	20s
Check if generated files are up to date	3m 28s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.3.2)	1m 59s
Windows MSI${{ '' }}	0s
Hypothesis tests on Ubuntu	3m 46s
CIFuzz (address)	3m 33s
CIFuzz (undefined)	3m 33s
CIFuzz (memory)	3m 32s
Thread sanitizer / Thread sanitizer	3m 45s
Thread sanitizer (free-threading) / Thread sanitizer	3m 48s
WASI / build and test	3m 45s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	3m 34s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	3m 36s
macOS / build and test (macos-13)	3m 48s
Ubuntu / build and test (ubuntu-22.04)	3m 41s
Ubuntu (free-threading) / build and test (ubuntu-22.04)	3m 45s
Windows / build (arm64)	3m 19s
Windows (free-threading) / build (arm64)	3m 33s
Windows / build and test (Win32)	3m 30s
Windows (free-threading) / build and test (Win32)	3m 29s
Windows / build and test (x64)	3m 31s
Windows (free-threading) / build and test (x64)	3m 29s
Docs / Docs	2m 12s
Docs / Doctest	3m 44s
Docs / Docs (Oldest Sphinx)	2m 16s
All required checks pass	3s
	1h 29m 31s

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