CI: Set codepage to utf-8 for msys2 tests run. #1014

Job	Run time
Windows-2022 [arch x64, toolset v143, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	18m 0s
Windows-2022 [arch x64, toolset v143, backend botan, build shared libs off, use CMake prefix path off, sanitizers off]	18m 9s
Windows-2022 [arch x64, toolset v143, backend openssl, build shared libs off, use CMake prefix path on, sanitizers off]	14m 59s
Windows-2022 [arch x64, toolset v143, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	14m 47s
Windows-2022 [arch x64, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	19m 56s
Windows-2022 [arch x64, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path off, sanitizers off]	16m 39s
Windows-2022 [arch x64, toolset ClangCL, backend openssl, build shared libs off, use CMake prefix path on, sanitizers off]	16m 45s
Windows-2022 [arch x64, toolset ClangCL, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	18m 38s
Windows-2022 [arch x64, toolset v143, backend botan, build shared libs off, use CMake prefix path off, sanitizers on]	27m 47s
Windows-2022 [arch Win32, toolset ClangCL, backend botan, build shared libs off, use CMake prefix path on, sanitizers off]	18m 49s
Windows-2022 [arch Win32, toolset v143, backend openssl, build shared libs off, use CMake prefix path off, sanitizers off]	13m 57s
	3h 18m 26s

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