Tests

Use `saturating_sub` for device lock comparison #1692

Job	Run time
Browser Tests	7m 42s
Core Tests on macOS (x86_64-apple-darwin)	7m 29s
Check Formatting	2m 48s
Core Tests on Linux (wasm32-unknown-unknown)	2m 44s
Core Tests on Windows (x86_64-pc-windows-msvc)	12m 15s
Rust Wasm Checks	1m 55s
Build WASM binary	8m 30s
Core Tests on Windows (i686-pc-windows-msvc)	9m 51s
Core Tests on Linux (x86_64-unknown-linux-gnu)	4m 17s
	57m 31s

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