Replace AlignedBoxedSlice with aligned_vec::ABox #5128

Job	Run time
rustfmt-clippy	1m 37s
msrv	2m 12s
wasi	1m 33s
build-windows (cargo-build, x86_64-pc-windows-msvc)	3m 56s
build-macos (Cargo build (x64), cargo-build, x86_64-apple-darwin)	5m 31s
build-windows (cargo-test, x86_64-pc-windows-msvc)	6m 12s
build-macos (Cargo test (x64), cargo-test, x86_64-apple-darwin)	5m 30s
build-unix (beta-build)	2m 46s
build-windows (cargo-c, x86_64-pc-windows-gnu)	7m 15s
build-macos (Cargo C-build (x64), cargo-c, x86_64-apple-darwin)	5m 11s
build-unix (1.70.0-tests)	5m 23s
build-macos (Cargo build (Arm64), cargo-build, aarch64-apple-darwin)	4m 34s
build-unix (aom-tests)	5m 37s
build-macos (Cargo C-build (Arm64), cargo-c, aarch64-apple-darwin)	4m 25s
build-unix (dav1d-tests)	5m 44s
build-unix (no-asm-tests)	9m 11s
build-unix (grcov-codecov)	14m 20s
build-unix (bench)	3m 39s
build-unix (doc)	3m 51s
build-unix (cargo-c)	3m 36s
build-unix (check-no-default)	1m 27s
build-unix (check-extra-feats)	2m 33s
build-unix (check-unstable-feats)	2m 35s
build-unix (fuzz)	5m 55s
build-unix (dav1d-tests-arm64, stable)	6m 24s
	2h 0m 57s

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