Tests

fix: ancient class hash calculation #911

Job	Run time
no-std build	2m 31s
WASM tests	6m 26s
Unix tests (ubuntu-latest, stable)	3m 50s
Windows tests (stable, x86_64-pc-windows-gnu)	12m 41s
Unix tests (ubuntu-latest, nightly)	3m 21s
Unix tests (macos-11, stable)	4m 56s
Windows tests (stable, x86_64-pc-windows-msvc)	7m 15s
Unix tests (macos-11, nightly)	4m 54s
Windows tests (nightly, x86_64-pc-windows-gnu)	7m 26s
Windows tests (nightly, x86_64-pc-windows-msvc)	6m 19s
	59m 39s

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