GH-118289: Fix handling of non-directories in `os.path.realpath()` #115392

Job	Run time
Check for source changes	13s
Check if generated files are up to date	5m 2s
Hypothesis tests on Ubuntu	5m 33s
Address sanitizer	13m 45s
Ubuntu SSL tests with OpenSSL (1.1.1w)	2m 1s
Ubuntu SSL tests with OpenSSL (3.0.13)	2m 8s
Ubuntu SSL tests with OpenSSL (3.1.5)	2m 8s
CIFuzz	0s
Ubuntu SSL tests with OpenSSL (3.2.1)	1m 54s
Windows / build and test (x64)	17m 49s
Windows / build and test (x86)	20m 44s
Windows / build (arm64)	3m 23s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 13s
macOS / build and test (macos-13)	11m 50s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 4s
Thread sanitizer / Thread sanitizer	4m 21s
Ubuntu / build and test	12m 3s
Ubuntu (free-threading) / build and test	9m 38s
Windows (free-threading) / build and test (x64)	20m 43s
Windows (free-threading) / build (arm64)	4m 16s
Windows (free-threading) / build and test (x86)	23m 18s
Thread sanitizer (free-threading) / Thread sanitizer	7m 14s
WASI / build and test	10m 42s
Docs / Docs	2m 5s
Docs / Docs (Oldest Sphinx)	2m 6s
Docs / Doctest	15m 58s
All required checks pass	3s
	3h 29m 14s

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