Rust: remove shipped feature flag #1029

Job	Run time
Upload debug artifacts after failure in analyze (stable-v2.20.3)	1m 55s
Upload debug artifacts after failure in analyze (default)	3m 3s
Upload debug artifacts after failure in analyze (nightly-latest)	3m 15s
Upload debug artifacts after failure in analyze (linked)	3m 5s
Download and check debug artifacts after failure in analyze	11s
	11m 29s

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