* Revert "unnecessary this in field initializers (#22522)" This reverts commit5de96bb734. * Revert "Use unsafePackageSerialization when running tests (#22407)" This reverts commit4bd6ad7395. * Revert "Roll engine f6af1f20ba92..b59c86493159 (3 commits) (#22538)" This reverts commit85a4591aa3.