DisplayController should deep compare mPerDisplayBounds

- In CHANGE_SUPPORTED_BOUNDS check, it uses Map.equals, but as the value is a primitive array WindowBounds[], equals check does not deep compare the arrays and may result in false negative
- One example is when fontScale changes, DisplayController re-create bounds from WindowManagerProxy, result in new WindowBounds[] created, and the shallow compare results in unexpected CHANGE_SUPPORTED_BOUNDS

Fix: 282736623
Test: DisplayControllerTest
Change-Id: I3897595c58559192b951ecfee7c9f62a07dafe1f

src/com/android/launcher3/util/MainThreadInitializedObject.java

@@ -131,7 +131,8 @@ public class MainThreadInitializedObject<T> {
          * Find a cached object from mObjectMap if we have already created one. If not, generate
          * an object using the provider.
          */
-        private <T> T getObject(MainThreadInitializedObject<T> object, ObjectProvider<T> provider) {
+        protected <T> T getObject(MainThreadInitializedObject<T> object,
+                ObjectProvider<T> provider) {
             synchronized (mDestroyLock) {
                 if (mDestroyed) {
                     Log.e(TAG, "Static object access with a destroyed context");