Rust

Fix uefi-raw MSRV build, and improve CI for MSRV #6184

Job	Run time
Build (stable MSRV)	33s
Build (feature permutations)	2m 57s
Build (uefi-raw MSRV)	26s
Lints	57s
Nightly (build, test, doc)	1m 39s
Unit + Doc Tests	1m 47s
Integration Test (AArch64)	1m 13s
Integration Test (IA-32)	1m 31s
Integration Test (x86_64)	1m 27s
Integration Test (x86_64 Windows)	4m 39s
Build Standard Binary (nightly)	24s
Test Coverage	32s
Unit + Doc Tests (Miri)	1m 6s
	19m 11s

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