Rust: remove shipped feature flag #1031

Job	Run time
Upload debug artifacts after failure in analyze (linked)	3m 4s
Upload debug artifacts after failure in analyze (nightly-latest)	3m 12s
Upload debug artifacts after failure in analyze (default)	3m 15s
Upload debug artifacts after failure in analyze (stable-v2.20.3)	2m 6s
Download and check debug artifacts after failure in analyze	16s
	11m 53s

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