Update rand test #2921

Job	Run time
rustfmt	22s
dist (ubuntu-20.04, x86_64-unknown-linux-gnu)	2m 18s
test (ubuntu-latest, x86_64-unknown-linux-gnu)	13m 3s
dist (macos-latest, x86_64-apple-darwin)	4m 34s
test (macos-latest, x86_64-apple-darwin)	17m 40s
test_llvm	5m 35s
bench	10m 32s
dist (ubuntu-latest, x86_64-pc-windows-gnu)	2m 44s
test (ubuntu-latest, x86_64-pc-windows-gnu)	10m 53s
dist (windows-latest, x86_64-pc-windows-msvc)	4m 13s
test (ubuntu-latest, aarch64-unknown-linux-gnu)	6m 13s
dist (windows-latest, x86_64-pc-windows-gnu)	5m 1s
test (ubuntu-latest, s390x-unknown-linux-gnu)	8m 0s
test (windows-latest, x86_64-pc-windows-msvc)	22m 47s
test (windows-latest, x86_64-pc-windows-gnu)	21m 54s
release	0s
	2h 15m 49s

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