Implement relaxed rule for opaque struct members #596

Job	Run time
linux (clang, clang++, Debug)	8m 38s
android (ON, 23.2.8568313)	12m 30s
emscripten	2m 43s
linux (clang, clang++, Release)	9m 2s
Linux Backcompat	18m 3s
android (ON, 25.2.9519653)	9m 3s
linux (gcc, g++, Debug)	12m 14s
android (OFF, 23.2.8568313)	8m 32s
linux (gcc, g++, Release)	11m 42s
android (OFF, 25.2.9519653)	8m 18s
linux-asan (gcc, g++, Debug, -fsanitize=address)	14m 49s
macos (macos-11, clang, clang++, Debug)	13m 1s
linux-asan (gcc, g++, Debug, -fsanitize=thread)	31m 2s
macos (macos-11, clang, clang++, Release)	14m 42s
windows (windows-2019, windows, Debug)	12m 23s
macos (macos-11, gcc, g++, Debug)	16m 49s
windows (windows-2019, windows, Release)	10m 18s
macos (macos-11, gcc, g++, Release)	14m 19s
macos (macos-12, clang, clang++, Debug)	16m 25s
macos (macos-12, clang, clang++, Release)	11m 29s
macos (macos-12, gcc, g++, Debug)	10m 6s
macos (macos-12, gcc, g++, Release)	13m 46s
	4h 39m 54s

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