Tests

Improve projective mul by scalar perf #1088

Job	Run time
no-std build	1m 56s
Unix tests (ubuntu-latest, stable)	1m 42s
WASM tests	3m 50s
Windows tests (stable, x86_64-pc-windows-gnu)	5m 13s
Unix tests (ubuntu-latest, nightly)	2m 22s
Windows tests (stable, x86_64-pc-windows-msvc)	14m 9s
Unix tests (macos-11, stable)	14m 36s
Windows tests (nightly, x86_64-pc-windows-gnu)	11m 34s
Unix tests (macos-11, nightly)	14m 41s
Windows tests (nightly, x86_64-pc-windows-msvc)	8m 9s
	1h 18m 12s

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