Revert "Csharp explicitly add cdecl" #2869

Job	Run time
debug (macos-latest)	13m 22s
debug64 (macos-latest)	12m 58s
debug_all_tests (macos-latest)	8m 30s
debug64_all_tests (macos-latest)	18m 7s
release (macos-latest)	10m 14s
release_all_tests (macos-latest)	12m 26s
Release64 (macos-latest)	11m 51s
Release64_all_tests (macos-latest)	11m 22s
	1h 38m 50s

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