Added find_if and find_if_not tests #688

Job	Run time
build (LLVM-Clang-16, Headers, Debug)	1m 2s
build (LLVM-Clang-16, Headers, Release)	1m 34s
build (LLVM-Clang-17, Headers, Debug)	1m 13s
build (LLVM-Clang-17, Headers, Release)	1m 41s
build (LLVM-Clang-17, Module, Debug)	1m 7s
build (LLVM-Clang-17, Module, Release)	1m 56s
build (LLVM-Clang-18, Headers, Debug)	1m 10s
build (LLVM-Clang-18, Headers, Release)	1m 33s
build (LLVM-Clang-18, Module, Debug)	1m 18s
build (LLVM-Clang-18, Module, Release)	1m 56s
build (LLVM-Clang-19, Headers, Debug)	1m 31s
build (LLVM-Clang-19, Headers, Release)	1m 22s
build (LLVM-Clang-19, Module, Debug)	1m 41s
build (LLVM-Clang-19, Module, Release)	1m 26s
	20m 30s

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