Cache compiler versions detected #1010

Job	Run time
Test CUDA support	20s
Test (stable)	56s
Clippy	7s
Test (beta)	43s
Test aarch64-apple-tvos	1m 57s
MSRV (ubuntu-latest)	19s
Test (nightly)	37s
Test (linux32)	1m 10s
MSRV (windows-latest)	39s
Rustfmt	3s
Test (macos)	1m 18s
Test (aarch64-ios)	1m 14s
Test (win32)	1m 18s
Test (win64)	2m 22s
Test (mingw32)	2m 0s
Test (mingw64)	1m 44s
Test (windows-2019)	1m 58s
Test (windows-aarch64, windows-latest, stable, aarch64-pc-windows-msvc, --no-run)	2m 12s
	20m 57s

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