meson CI: update clang to 19 (backport #3042) #1371

Job	Run time
MSYS2-UCRT64-deps=enabled	5m 1s
Linux-GCC7-deps=forcefallback	1m 44s
MSYS2-CLANG64-deps=enabled	3m 46s
Linux-Clang7-deps=forcefallback	1m 50s
Linux-GCC7-deps=default	1m 32s
Linux-Clang7-deps=default	1m 21s
MSYS2-UCRT64-deps=disabled	3m 27s
Linux-GCC13-deps=forcefallback	8m 5s
Linux-Clang19-deps=forcefallback	3m 6s
MSYS2-CLANG64-deps=disabled	3m 11s
Linux-GCC13-deps=default	5m 39s
Linux-Clang19-deps=default	2m 13s
MSVC-forcefallback-x64	3m 44s
clang-cl-forcefallback	4m 49s
MSVC-forcefallback-x86	4m 21s
clang-cl-default	3m 13s
MSVC-default-x64	2m 40s
FreeBSD	4m 8s
MSVC-default-x86	3m 13s
Emscripten	2m 44s
macOS-deps=enabled	1m 40s
macOS-deps=disabled	51s
	1h 12m 18s

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