Backport miscellaneous commits from dav1d 1.2.0 (#829) #3776

Job	Run time
test-on-macos-latest	5m 47s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, release, --release --no-default-features --featu...	2m 7s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, release, --release --no-default-features --featu...	2m 14s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, release, --release --no-default-features --featu...	1m 51s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, opt-dev, --profile opt-dev, 2)	2m 27s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, opt-dev, --profile opt-dev, 2, -f 1)	2m 25s
test-on-ubuntu-latest (x86_64-unknown-linux-gnu, opt-dev, --profile opt-dev, 2, -f 2)	3m 14s
test-on-ubuntu-latest (i686-unknown-linux-gnu, release, --release --no-default-features --feature...	2m 9s
test-on-ubuntu-latest (i686-unknown-linux-gnu, release, --release --no-default-features --feature...	2m 11s
test-on-ubuntu-latest (i686-unknown-linux-gnu, release, --release --no-default-features --feature...	2m 5s
test-on-ubuntu-latest (i686-unknown-linux-gnu, opt-dev, --profile opt-dev, 2)	2m 4s
test-on-ubuntu-latest (i686-unknown-linux-gnu, opt-dev, --profile opt-dev, 2, -f 1)	1m 57s
test-on-ubuntu-latest (i686-unknown-linux-gnu, opt-dev, --profile opt-dev, 2, -f 2)	2m 40s
	33m 11s

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