gh-125873: Improve error message when PYTHONHOME is invalid #130604

Job	Run time
Change detection / Compute changed files	9s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.0.15)	2m 9s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.1.7)	2m 11s
Check if Autoconf files are up to date	20s
Check if generated files are up to date	3m 36s
Address sanitizer	7m 24s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.2.3)	2m 27s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.3.2)	2m 15s
Windows MSI${{ '' }}	0s
CIFuzz (address)	20m 0s
Hypothesis tests on Ubuntu	5m 18s
CIFuzz (undefined)	21m 38s
CIFuzz (memory)	20m 38s
Thread sanitizer / Thread sanitizer	3m 7s
Thread sanitizer (free-threading) / Thread sanitizer	7m 17s
WASI / build and test	6m 17s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	4m 53s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	4m 28s
macOS / build and test (macos-13)	9m 57s
Ubuntu / build and test (ubuntu-22.04)	7m 13s
Ubuntu (free-threading) / build and test (ubuntu-22.04)	9m 16s
Windows / build (arm64)	3m 9s
Windows (free-threading) / build (arm64)	3m 11s
Windows / build and test (Win32)	16m 17s
Windows (free-threading) / build and test (Win32)	24m 6s
Windows / build and test (x64)	16m 25s
Windows (free-threading) / build and test (x64)	21m 59s
Docs / Docs	2m 2s
Docs / Docs (Oldest Sphinx)	2m 3s
Docs / Doctest	28m 20s
All required checks pass	1s
	4h 18m 6s

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