android-interop-testing: Fix compilation errors

Author: ejona86

android-interop-testing/app/src/main/java/io/grpc/android/integrationtest/InteropTester.java

@@ -46,8 +46,8 @@
 import io.grpc.android.integrationtest.nano.Messages.StreamingOutputCallResponse;
 import io.grpc.android.integrationtest.nano.TestServiceGrpc;
 import io.grpc.android.integrationtest.nano.UnimplementedServiceGrpc;
+import io.grpc.internal.testing.StreamRecorder;
 import io.grpc.stub.StreamObserver;
-import io.grpc.testing.StreamRecorder;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.Arrays;