qt module: allow has_tools to specify which tools to check #16627

Job	Run time
Arch / PyPy	19m 44s
Ubuntu Rolling (gcc, g++)	19m 25s
Ubuntu Rolling (--unity=on -Ddefault_library=static, --no-unittests, gcc, g++)	14m 15s
Arch Linux	19m 36s
Ubuntu Rolling (-Ddefault_library=both, --no-unittests, gcc, g++)	13m 55s
CUDA (on Arch)	7m 42s
Ubuntu Rolling (clang, clang++)	22m 25s
Fedora	19m 51s
Ubuntu Rolling (--unity=on, --no-unittests, clang, clang++)	15m 49s
Gentoo	21m 28s
Ubuntu Rolling (--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json, 0, gcc, g++)	14m 34s
OpenSUSE	16m 53s
Ubuntu Bionic	15m 26s
Ubuntu Rolling (--cross ubuntu-armhf.json --cross linux-mingw-w64-64bit.json, --unity=on, gcc, g++)	13m 29s
	3h 54m 32s

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