Support MSYS2's CLANGARM64 environment on ARM64 Windows #12725

Job	Run time
x86_64-gnu-test (1.7.3)	33m 15s
x86_64-musl-test	39m 6s
x86_64-gnu-test (1.8.2)	35m 13s
x86_64-gnu-test-preview_mt	5m 33s
x86_64-gnu-test (1.9.2)	34m 52s
x86_64-gnu-test (1.10.1)	34m 45s
check_format	1m 32s
x86_64-gnu-test (1.11.2)	33m 39s
x86_64-gnu-test (1.12.2)	33m 23s
x86_64-gnu-test (1.13.3)	35m 7s
x86_64-gnu-test (1.14.0)	33m 58s
x86_64-gnu-test (1.0.0, FLAGS=-Dwithout_ffi USE_PCRE1=true)	33m 20s
x86_64-gnu-test (1.1.1, FLAGS=-Dwithout_ffi USE_PCRE1=true)	34m 1s
x86_64-gnu-test (1.2.2, USE_PCRE1=true)	36m 15s
x86_64-gnu-test (1.3.2, USE_PCRE1=true)	36m 28s
x86_64-gnu-test (1.4.1, USE_PCRE1=true)	34m 36s
x86_64-gnu-test (1.5.1, USE_PCRE1=true)	34m 16s
x86_64-gnu-test (1.6.2, USE_PCRE1=true)	33m 23s
	9h 22m 42s

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