Revert "Roll engine to ceb6d05c2fb3bd5c31a25d4b08be9fd97b55a446 (#11933)" (#11959)

This roll caused performance regressions in benchmarks:
* complex_layout_scroll_perf
* flutter_gallery_transition_perf

This reverts commit f430a45a.

bin/internal/engine.version

-ceb6d05c2fb3bd5c31a25d4b08be9fd97b55a446
+29e0c1c2814ebbb325f1ddbc5d365a2960ec4575

packages/flutter_driver/test/flutter_driver_test.dart

@@ -354,16 +354,23 @@ Future<Map<String, dynamic>> makeMockResponse(
   });
 }
 
+@proxy
 class MockVMServiceClient extends Mock implements VMServiceClient { }
 
+@proxy
 class MockVM extends Mock implements VM { }
 
+@proxy
 class MockIsolate extends Mock implements VMRunnableIsolate { }
 
+@proxy
 class MockVMPauseStartEvent extends Mock implements VMPauseStartEvent { }
 
+@proxy
 class MockVMPauseBreakpointEvent extends Mock implements VMPauseBreakpointEvent { }
 
+@proxy
 class MockVMResumeEvent extends Mock implements VMResumeEvent { }
 
+@proxy
 class MockPeer extends Mock implements rpc.Peer { }