crt: Add ARM64EC setjmp and longjmp implementation #31

Job	Run time
llvm-mingw (ucrtbase)	23m 44s
llvm-mingw (ucrt)	23m 35s
gcc (ucrt, i686)	19m 47s
gcc (ucrt, x86_64)	19m 37s
gcc (msvcrt, i686)	18m 41s
llvm-mingw (msvcrt)	23m 48s
gcc (msvcrt, x86_64)	19m 31s
gcc-cross (msvcrt, i686)	17m 52s
gcc-cross (msvcrt, x86_64)	17m 28s
gcc-cross (ucrt, x86_64)	18m 2s
gcc-cross (ucrt, i686)	17m 5s
test-libcxx (x86_64)	1h 14m 37s
test-libcxx (x86_64, i686-w64-mingw32-)	1h 13m 32s
test-ffmpeg (i686)	17m 30s
test-ffmpeg (x86_64)	18m 30s
test-llvm-mingw (x86_64, ucrtbase)	3m 45s
linux-test-cross-build-ffmpeg (x86_64)	5m 54s
test-llvm-mingw (x86_64, msvcrt)	3m 28s
test-llvm-mingw (i686, ucrt)	3m 34s
test-llvm-mingw (i686, ucrtbase)	3m 44s
linux-test-cross-build-ffmpeg (i686)	5m 11s
linux-test-cross-build-ffmpeg (armv7)	4m 20s
test-llvm-mingw (x86_64, ucrt)	3m 33s
linux-test-cross-build-ffmpeg (aarch64)	4m 46s
test-llvm-mingw (i686, msvcrt)	3m 39s
test-gcc (ucrt, i686)	42s
test-gcc (ucrt, x86_64)	42s
test-gcc (msvcrt, x86_64)	43s
test-gcc (msvcrt, i686)	38s
	7h 27m 58s

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