Fix or silence `wasmi_wast` warnings #4421

Job	Run time
Test (ubuntu-latest)	1m 47s
Build	1m 44s
Audit	2m 32s
Test (windows-latest)	4m 46s
Clippy	58s
Test (macos-latest)	2m 12s
Coverage	4m 4s
Documentation	47s
Formatting	15s
Fuzz (translate)	3m 21s
Fuzz (execute)	3m 31s
Check mininum supported Rust version	26s
Fuzz (differential)	3m 44s
Miri	6m 55s
Miri (spec)	6m 33s
Test (Address Sanitizer)	2m 36s
uDeps	54s
	47m 5s

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