test

Reduce boilerplate code in `windows-core` crate for `VARIANT` support… #2604

Job	Run time
check (stable, x86_64-pc-windows-msvc, x86_64-pc-windows-msvc)	19m 37s
check (nightly, x86_64-pc-windows-msvc, i686-pc-windows-msvc)	18m 47s
check (nightly, x86_64-pc-windows-gnu, x86_64-pc-windows-gnu)	21m 49s
check (stable, x86_64-pc-windows-gnu, i686-pc-windows-gnu)	22m 2s
check (stable, x86_64-pc-windows-msvc, aarch64-pc-windows-msvc, --no-run)	19m 46s
check (nightly, x86_64-pc-windows-msvc, aarch64-pc-windows-msvc, --no-run)	19m 54s
	2h 1m 55s

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