Revert "Csharp explicitly add cdecl" #2870

Job	Run time
debug_all_tests (macos-latest)	7m 15s
debug64 (macos-latest)	11m 45s
debug (macos-latest)	12m 20s
debug64_all_tests (macos-latest)	35m 3s
release_all_tests (macos-latest)	10m 30s
release (macos-latest)	6m 39s
Release64 (macos-latest)	17m 39s
Release64_all_tests (macos-latest)	13m 19s
	1h 54m 30s

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