ctutils: add size integers implementations (#1416) #2194

Job	Run time
test (stable)	16s
test (1.85.0)	19s
minimal-versions / minimal-versions	14s
build (stable, wasm32-unknown-unknown)	19s
build (stable, thumbv7em-none-eabi)	19s
build (1.85.0, wasm32-unknown-unknown)	17s
build (1.85.0, thumbv7em-none-eabi)	18s
	2m 2s

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