block-padding: implement ISO 10126 #409

Job	Run time
build (1.60.0, armv7a-none-eabi)	2m 28s
build (1.60.0, thumbv7em-none-eabi)	2m 6s
build (1.60.0, wasm32-unknown-unknown)	2m 30s
build (stable, armv7a-none-eabi)	11s
build (stable, thumbv7em-none-eabi)	8s
build (stable, wasm32-unknown-unknown)	11s
aarch64 (aarch64-unknown-linux-gnu, 1.60.0)	2m 41s
aarch64 (aarch64-unknown-linux-gnu, stable)	52s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.60.0, sudo apt update && sudo apt install gcc-mult...	2m 52s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	1m 1s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.60.0)	2m 37s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	35s
test (x86_64-apple-darwin, macos-latest, 1.60.0)	2m 36s
test (x86_64-apple-darwin, macos-latest, stable)	34s
test (x86_64-pc-windows-msvc, windows-latest, 1.60.0)	3m 23s
test (x86_64-pc-windows-msvc, windows-latest, stable)	2m 11s
cross (powerpc-unknown-linux-gnu, 1.60.0)	3m 7s
cross (powerpc-unknown-linux-gnu, stable)	51s
minimal-versions / minimal-versions	57s
	31m 51s

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