This reverts merge commit 2b1bd20834 (#31125)
Two CircleCI jobs on the staging-to-main promotion went red the moment
that PR landed. proxy_multi_instance_tests boots two proxies against one
database, and both now race the same migration:
Error: P3018 A migration failed to apply
Database error code: 40P01, deadlock detected
Process 73 waits for ShareLock on virtual transaction 4/11;
blocked by process 75. Process 75 waits for ExclusiveLock on
advisory lock [16384,0,72707369,1]; blocked by process 73
Neither proxy comes up, so the job times out after 300s waiting on
localhost:4000. The same wait took 36.5s on the last green run
Timeline: #31125 merged at 18:46:14Z and the failing run started at
18:49:59Z. The merge commit is not an ancestor of the last green
revision (194a3cc) and is an ancestor of the first failing one
(01de2837)
The v2 resolver was meant to avoid exactly this class of contention, so
the deadlock looks like a bug in it rather than a reason to abandon it.
Putting the default back to v1 buys time to fix it without holding up
the release
fd72a39b1b