Enable Fabric test using Fabric C++ implementation

Summary:
This diff:
- Disables all tests but one of FabricViewTest
- Disables all tests but one of FabricBenchmarkTest
- Changes ReactAppTestActivity to run with Hermes

The reason there is only one test running in each test class, is because the tear down process of Fabric is still flaky and it produces crashes when restarting RN. We are working on this right now and we will enable the rest of the tests after that's fixed.

Reviewed By: achen1

Differential Revision: D9890700

fbshipit-source-id: a8716481eff15b77bd12b38aaaefd4e282c71f3b

ReactAndroid/src/main/java/com/facebook/react/bridge/CatalystInstanceImpl.java

@@ -25,7 +25,6 @@ import com.facebook.react.common.ReactConstants;
 import com.facebook.react.common.annotations.VisibleForTesting;
 import com.facebook.systrace.Systrace;
 import com.facebook.systrace.TraceListener;
-import java.lang.annotation.Native;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Collection;

ReactAndroid/src/main/java/com/facebook/react/bridge/ProxyJavaScriptExecutor.java

@@ -7,10 +7,9 @@
 
 package com.facebook.react.bridge;
 
-import javax.annotation.Nullable;
-
 import com.facebook.jni.HybridData;
 import com.facebook.proguard.annotations.DoNotStrip;
+import javax.annotation.Nullable;
 
 /**
  * JavaScript executor that delegates JS calls processed by native code back to a java version