Rust: remove shipped feature flag #5234

Job	Run time
Ruby analysis (ubuntu-latest, linked)	1m 3s
Ruby analysis (macos-latest, linked)	1m 20s
Ruby analysis (macos-latest, default)	1m 47s
Ruby analysis (ubuntu-latest, nightly-latest)	1m 6s
Ruby analysis (ubuntu-latest, default)	1m 3s
Ruby analysis (macos-latest, nightly-latest)	1m 23s
	7m 42s

Provide feedback