Add --release flag #2397

Job	Run time
maybe-expedite	5s
lint	6m 27s
test (third-party, bincode, stable, false)	18m 59s
test (third-party, bincode, stable, true)	18m 59s
test (third-party, bincode, nightly, false)	16m 6s
test (third-party, bincode, nightly, true)	16m 47s
test (third-party, postcard, stable, false)	17m 4s
test (third-party, postcard, stable, true)	17m 38s
test (third-party, postcard, nightly, false)	17m 2s
test (third-party, postcard, nightly, true)	17m 46s
test (other, bincode, stable, false)	33m 38s
test (other, bincode, stable, true)	33m 20s
test (other, bincode, nightly, false)	39m 54s
test (other, bincode, nightly, true)	39m 47s
test (other, postcard, stable, false)	31m 36s
test (other, postcard, stable, true)	34m 37s
test (other, postcard, nightly, false)	38m 21s
test (other, postcard, nightly, true)	40m 9s
all-checks	1s
	7h 18m 16s

Provide feedback