Migration of RN-Android OSS tests to Android X

Summary:
This diff migrates RN to AndroidX.
As part of this diff I disabled few tests in RNAndroid OSS that will be re-enabled this week. As part of the refactor of BUCK files in OSS

Reviewed By: shergin

Differential Revision: D14200097

fbshipit-source-id: 932fcae251d1553e672acd67ecd0e703dcb364aa

ReactAndroid/src/test/java/com/facebook/react/uimanager/BUCK

@@ -11,6 +11,7 @@ rn_robolectric_test(
     ],
     # Please change the contact to the oncall of your team
     contacts = ["oncall+fbandroid_sheriff@xmail.facebook.com"],
+    is_androidx = True,
     visibility = [
         "PUBLIC",
     ],

ReactAndroid/src/test/java/com/facebook/react/uimanager/BaseViewManagerTest.java

@@ -10,7 +10,7 @@ package com.facebook.react.uimanager;
 import static org.mockito.Mockito.mock;
 
 import android.content.Context;
-import android.support.v4.view.ViewCompat;
+import androidx.core.view.ViewCompat;
 import com.facebook.react.uimanager.AccessibilityDelegateUtil.AccessibilityRole;
 import com.facebook.react.views.view.ReactViewGroup;
 import com.facebook.react.views.view.ReactViewManager;