Add `set_cert_verify_callback` (`SSL_CTX_set_cert_verify`) #942

Job	Run time
rustfmt	9s
Test (stable)	4m 38s
Test (arm-android)	2m 0s
clippy	3m 16s
Cross build from macOS to Linux (x86_64-unknown-linux-gnu)	2m 40s
Test (arm64-android)	2m 10s
Test (i686-android)	3m 39s
Test (x86_64-android)	2m 3s
Test features	7m 30s
Cross build from macOS to Linux (FIPS) (x86_64-unknown-linux-gnu)	2m 31s
Test (aarch64-ios)	4m 1s
Test (aarch64-ios-sim)	2m 33s
Test (x86_64-ios)	2m 23s
Test FIPS integration	2m 56s
Test (i686-linux)	2m 21s
Test (arm-linux)	2m 41s
Test (aarch64-linux)	2m 31s
Test (arm64-macos)	2m 18s
Test (x86_64-macos)	2m 48s
Test (x86_64-mingw)	5m 8s
Test (i686-msvc)	6m 42s
Test (x86_64-msvc)	6m 9s
	1h 13m 7s

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