zeroize_derive: fixup test suite [1.4] #1064

Job	Run time
cross (powerpc-unknown-linux-gnu, stable)	39s
aarch64 (aarch64-unknown-linux-gnu, 1.59.0)	6m 2s
cross (powerpc-unknown-linux-gnu, 1.56.0)	6m 1s
minimal-versions / minimal-versions	39s
build (1.56.0, armv7a-none-eabi)	5m 7s
aarch64 (aarch64-unknown-linux-gnu, stable)	49s
build (1.56.0, thumbv7em-none-eabi)	5m 38s
build (stable, wasm32-unknown-unknown)	12s
test (x86_64-apple-darwin, macos-latest, stable)	21s
build (stable, thumbv7em-none-eabi)	15s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	11s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.56.0)	5m 35s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	46s
test (x86_64-pc-windows-msvc, windows-latest, stable)	54s
test (x86_64-pc-windows-msvc, windows-latest, 1.56.0)	5m 54s
test (x86_64-apple-darwin, macos-latest, 1.56.0)	5m 21s
build (1.56.0, wasm32-unknown-unknown)	5m 33s
build (stable, armv7a-none-eabi)	7s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.56.0, sudo apt update && sudo apt install gcc-mult...	4m 56s
	55m 0s

Provide feedback