Fix build due to missing abstract method impl

getDisplay() was added to Context, which needs to be implemented
for BridgeContext.

Bug:28388969
Change-Id: I7b0ffcbbe252403e35f08d3fa40d6b0e4dbf0daa

tools/layoutlib/bridge/src/com/android/layoutlib/bridge/android/BridgeContext.java

@@ -1798,6 +1798,12 @@ public final class BridgeContext extends Context {
         return null;
     }
 
+    @Override
+    public Display getDisplay() {
+        // pass
+        return null;
+    }
+
     @Override
     public int getUserId() {
         return 0; // not used