Add differential testing harness #424

Job	Run time
Lint	5m 56s
Test (windows-2022, x86_64-pc-windows-msvc)	4m 51s
Test (ubuntu-24.04, aarch64-linux-android, x86_64-unknown-linux-gnu)	5m 7s
cargo-deny	1m 17s
Test (ubuntu-24.04, x86_64-unknown-linux-gnu)	5m 7s
Test (macOS-latest, x86_64-apple-darwin)	4m 51s
test_success	0s
	27m 9s

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