Flip blast sync flag

This enables blast sync when there's a request for a synchronized
transaction. This doesn't include enabling blast or blast sync for
SurfaceView

Test: go/wm-smoke
Test: split screen and pip with SurfaceView and secure content
Bug: 175229445
Change-Id: I01748a29bff051d633b51b1857a3e7523207dd17

services/core/java/com/android/server/wm/WindowManagerService.java

@@ -682,7 +682,7 @@ public class WindowManagerService extends IWindowManager.Stub
     // Whether the system should use BLAST for ViewRootImpl
     final boolean mUseBLAST;
     // Whether to enable BLASTSyncEngine Transaction passing.
-    final boolean mUseBLASTSync = false;
+    final boolean mUseBLASTSync = true;
 
     final BLASTSyncEngine mSyncEngine;