`LocalChain` with hardwired genesis block #4169

Job	Run time
Build and test (stable, true, --no-default-features)	4m 39s
Check no_std	1m 39s
clippy_check	8m 0s
Build and test (stable, true, --all-features)	4m 39s
Build and test (1.57.0, --no-default-features)	4m 23s
Check WASM	1m 13s
Build and test (1.57.0, --all-features)	4m 38s
Rust fmt	5s
	29m 16s

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