optimize `Step` impl for `VirtAddr` #2903

Job	Run time
Check Formatting	14s
kani	33s
Clippy	14s
Bootloader Integration Test (ubuntu-latest)	1m 16s
Semver Checks	20s
Test MSRV and Stable Features (nightly)	21s
Bootloader Integration Test (macos-latest)	2m 14s
Test (ubuntu-latest)	30s
Test MSRV and Stable Features (1.59)	3m 34s
Bootloader Integration Test (windows-latest)	3m 24s
Test (macos-latest)	48s
Test (windows-latest)	51s
	14m 19s

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