Add SSL_CTX_dup API #50

Job	Run time
compiler (gcc-7, ubuntu-20.04)	7m 49s
compiler (gcc-8, ubuntu-20.04)	6m 32s
compiler (gcc-9, ubuntu-20.04)	8m 34s
compiler (gcc-10, ubuntu-20.04)	7m 45s
compiler (gcc-11, ubuntu-22.04)	6m 24s
compiler (gcc-12, ubuntu-22.04)	7m 28s
compiler (gcc-13, ubuntu-22.04, ubuntu-toolchain-r/test)	7m 17s
compiler (clang-6.0, ubuntu-20.04)	7m 46s
compiler (clang-7, ubuntu-20.04)	6m 49s
compiler (clang-8, ubuntu-20.04)	6m 27s
compiler (clang-9, ubuntu-20.04)	6m 51s
compiler (clang-10, ubuntu-20.04)	6m 27s
compiler (clang-11, ubuntu-20.04)	6m 41s
compiler (clang-12, ubuntu-20.04)	7m 26s
compiler (clang-13, ubuntu-22.04)	6m 37s
compiler (clang-14, ubuntu-22.04)	6m 48s
compiler (clang-15, ubuntu-22.04, jammy)	6m 41s
compiler (clang-16, ubuntu-22.04, jammy)	6m 57s
	2h 7m 19s

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