Rust: remove shipped feature flag #5343

Job	Run time
Ruby analysis (macos-latest, linked)	1m 12s
Ruby analysis (ubuntu-latest, default)	52s
Ruby analysis (ubuntu-latest, nightly-latest)	50s
Ruby analysis (ubuntu-latest, linked)	51s
Ruby analysis (macos-latest, nightly-latest)	56s
Ruby analysis (macos-latest, default)	59s
	5m 40s

Provide feedback