[target-spec] actually deserialize target_family and target_endian co… #1352

Job	Run time
Build and test core crates (ubuntu-latest, 1.78)	2m 7s
Build and test (all features) (ubuntu-latest, 1.78)	3m 5s
Build documentation (ubuntu-latest)	1m 7s
Build and test core crates (ubuntu-latest, stable)	1m 45s
Build and test (all features) (ubuntu-latest, stable)	3m 4s
Build and test core crates (macos-14, 1.78)	1m 48s
Build and test (all features) (macos-14, 1.78)	2m 42s
Build and test core crates (macos-14, stable)	1m 38s
Lint	55s
Build and test (all features) (macos-14, stable)	2m 15s
Build and test core crates (windows-latest, 1.78)	4m 34s
Build and test (all features) (windows-latest, 1.78)	5m 54s
Build and test core crates (windows-latest, stable)	6m 51s
Build and test (all features) (windows-latest, stable)	5m 19s
Cross-compile to aarch64	1m 46s
cargo-compare extended tests (ubuntu-latest)	3m 7s
cargo-compare extended tests (macos-14)	2m 55s
	50m 52s

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