Add additional EVP_SKEY helpers #481

Job	Run time
compiler (gcc-7, ubuntu-20.04)	45s
compiler (gcc-8, ubuntu-20.04)	42s
compiler (gcc-9, ubuntu-20.04)	39s
compiler (gcc-10, ubuntu-20.04)	38s
compiler (gcc-11, ubuntu-22.04)	38s
compiler (gcc-12, ubuntu-22.04)	53s
compiler (gcc-13, ubuntu-22.04, ubuntu-toolchain-r/test)	4m 12s
compiler (clang-6.0, ubuntu-20.04)	50s
compiler (clang-7, ubuntu-20.04)	52s
compiler (clang-8, ubuntu-20.04)	50s
compiler (clang-9, ubuntu-20.04)	58s
compiler (clang-10, ubuntu-20.04)	52s
compiler (clang-11, ubuntu-20.04)	43s
compiler (clang-12, ubuntu-20.04)	47s
compiler (clang-13, ubuntu-22.04)	48s
compiler (clang-14, ubuntu-22.04)	57s
compiler (clang-15, ubuntu-22.04, jammy)	53s
compiler (clang-16, ubuntu-22.04, jammy)	56s
compiler (clang-17, ubuntu-22.04, jammy)	57s
	18m 50s

Provide feedback