Rust

Fix uefi-raw MSRV build, and improve CI for MSRV #6183

Job	Run time
Integration Test (x86_64)	1m 22s
Integration Test (x86_64 Windows)	4m 51s
Build Standard Binary (nightly)	28s
Build (feature permutations)	3m 27s
Build (uefi-raw MSRV)	26s
Build (stable MSRV)	35s
Test Coverage	36s
Lints	56s
Unit + Doc Tests (Miri)	1m 43s
Nightly (build, test, doc)	2m 34s
Unit + Doc Tests	1m 39s
Integration Test (AArch64)	2m 14s
Integration Test (IA-32)	1m 29s
	22m 20s

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