chore(json-abi): clean up utils #2128

Job	Run time
features stable	2m 21s
features stable --all-targets	3m 19s
features nightly	1m 39s
features nightly --all-targets	2m 58s
miri --no-default-features	4m 47s
miri	4m 35s
wasm	41s
test ubuntu-latest stable --no-default-features	1m 18s
miri --all-features	7m 4s
check no_std	40s
test ubuntu-latest stable	1m 16s
test ubuntu-latest nightly --no-default-features	54s
clippy	44s
test ubuntu-latest nightly	48s
fmt	13s
docs	36s
test ubuntu-latest 1.79 --no-default-features	40s
test ubuntu-latest 1.79	37s
test windows-latest stable --no-default-features	3m 25s
test windows-latest stable	3m 23s
test windows-latest nightly --no-default-features	2m 5s
test windows-latest nightly	2m 18s
test windows-latest 1.79 --no-default-features	2m 27s
test windows-latest 1.79	1m 29s
test ubuntu-latest 1.79 --features json	43s
test windows-latest 1.79 --features json	1m 44s
test ubuntu-latest nightly --all-features	1m 8s
test windows-latest nightly --all-features	2m 51s
	56m 43s

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