gh-124570: ctypes: Run some Structure tests on Union as well #127938

Job	Run time
Change detection / Compute changed files	9s
Check if generated files are up to date	5m 17s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.0.15)	2m 2s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.1.7)	2m 9s
Docs	0s
Windows MSI${{ '' }}	0s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.2.3)	2m 19s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.3.2)	2m 8s
Address sanitizer	7m 46s
CIFuzz	0s
Hypothesis tests on Ubuntu	5m 30s
WASI / build and test	6m 5s
Thread sanitizer / Thread sanitizer	4m 54s
Thread sanitizer (free-threading) / Thread sanitizer	7m 24s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	8m 34s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 44s
macOS / build and test (macos-13)	9m 16s
Ubuntu / build and test (ubuntu-22.04)	6m 30s
Ubuntu (free-threading) / build and test (ubuntu-22.04)	16m 19s
Windows / build (arm64)	2m 52s
Windows (free-threading) / build (arm64)	2m 55s
Windows / build and test (Win32)	16m 27s
Windows (free-threading) / build and test (Win32)	24m 1s
Windows / build and test (x64)	15m 34s
Windows (free-threading) / build and test (x64)	22m 10s
All required checks pass	1s
	2h 56m 6s

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