Remove unused type #7320

Job	Run time
build (windows-2019, Win32, v142, 17, Debug)	1m 52s
mingw (mingw64)	4m 26s
build (windows-2019, Win32, v142, 17, Release)	2m 0s
mingw (ucrt64)	4m 37s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	2m 10s
build (windows-2019, Win32, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	1m 55s
build (windows-2019, x64, v141, 14, Debug)	1m 24s
build (windows-2019, x64, v141, 14, Release)	2m 11s
build (windows-2019, x64, v141, 17, Debug)	2m 15s
build (windows-2019, x64, v141, 17, Release)	2m 15s
build (windows-2019, x64, v142, 17, Debug)	1m 28s
build (windows-2019, x64, v142, 17, Release)	2m 24s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Debug)	1m 28s
build (windows-2019, x64, v142, 17, -DBUILD_SHARED_LIBS=ON, Release)	2m 17s
build (windows-2019, x64, v142, 20, Debug)	2m 29s
build (windows-2019, x64, v142, 20, Release)	3m 23s
build (windows-2022, x64, v143, Debug, 20)	1m 39s
	40m 13s

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