add -Wimplicit-int-float-conversion flag in test build for clang and … #1636

Job	Run time
mingw (mingw64, Release, 17, ON)	15m 15s
mingw (ucrt64, Release, 17, ON)	15m 51s
msvc (windows-2022, x64, Debug, 17, ON)	8m 1s
msvc (windows-2022, x64, Debug, 20, ON)	9m 26s
msvc (windows-2022, x64, Release, 17, ON)	17m 0s
msvc (windows-2022, x64, Release, 20, ON)	20m 47s
msvc (windows-2022, x64, Release, 17, OFF, -DQUILL_NO_EXCEPTIONS=ON -DQUILL_BUILD_TESTS=ON)	2m 28s
msvc (windows-2022, ARM64, Release, 17, OFF)	3m 52s
	1h 32m 40s

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