Online DDL: better support for subsecond `--force-cut-over-after` DDL strategy flag value. #740

Job	Run time
Set push variable	1s
Build and push vttestserver (mysql80)	2m 6s
Build and push lite (latest)	2m 20s
Build and push lite (percona80)	2m 22s
Build and push (bullseye, vtadmin)	1m 21s
Build and push (bullseye, vtorc)	35s
Build and push (bullseye, vtgate)	44s
Build and push (bullseye, vttablet)	35s
Build and push (bullseye, mysqlctld)	38s
Build and push (bullseye, mysqlctl)	32s
Build and push (bullseye, vtctl)	39s
Build and push (bullseye, vtctlclient)	38s
Build and push (bullseye, vtctld)	1m 12s
Build and push (bullseye, vtctldclient)	44s
Build and push (bullseye, logrotate)	23s
Build and push (bullseye, logtail)	28s
Build and push (bullseye, vtbackup)	41s
Build and push (bullseye, vtexplain)	37s
Build and push (bookworm, vtadmin)	1m 20s
Build and push (bookworm, vtorc)	42s
Build and push (bookworm, vtgate)	36s
Build and push (bookworm, vttablet)	41s
Build and push (bookworm, mysqlctld)	49s
Build and push (bookworm, mysqlctl)	37s
Build and push (bookworm, vtctl)	45s
Build and push (bookworm, vtctlclient)	31s
Build and push (bookworm, vtctld)	1m 17s
Build and push (bookworm, vtctldclient)	31s
Build and push (bookworm, logrotate)	24s
Build and push (bookworm, logtail)	23s
Build and push (bookworm, vtbackup)	38s
Build and push (bookworm, vtexplain)	43s
	26m 33s

Provide feedback