title: com.android.tools.r8.utils.AbortException zza already has a mappin
body: <p>I'm running instrumentation tests and getting this compile error:</p>
  
  <pre><code>org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformClassesAndResourcesWithR8ForDebugAndroidTest'.
          at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:151)
          at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:148)
          at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:191)
          at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:141)
          ...
  Caused by: java.lang.RuntimeException: com.android.tools.r8.CompilationFailedException: Compilation failed to complete
          at com.android.builder.profile.Recorder$Block.handleException(Recorder.java:55)
          at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:108)
          at com.android.build.gradle.internal.pipeline.TransformTask.transform(TransformTask.java:230)
          at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:103)
          at org.gradle.api.internal.project.taskfactory.IncrementalTaskInputsTaskAction.doExecute(IncrementalTaskInputsTaskAction.java:46)
          ...
  Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete
          at com.android.tools.r8.utils.z.a(:55)
          at com.android.tools.r8.R8.runForTesting(:3)
          at com.android.tools.r8.R8.run(:3)
          at com.android.builder.dexing.R8Tool.runR8(r8Tool.kt:195)
  
  Caused by: com.android.tools.r8.utils.AbortException: Error: offset: 0, line: 16559, column: 1, 'void zza(com.google.android.gms.common.internal.BaseGmsClient,int,android.os.IInterface)' already has a mapping
          at com.android.tools.r8.utils.Reporter.a(:21)
          at com.android.tools.r8.naming.SeedMapper$a.build(:1)
          ...
  </code></pre>
  
  <p>If I look in <code>app/build/outputs/mappings/debug/mapping.txt</code> I see that method listed twice.</p>
  
  <pre><code>com.google.android.gms.common.internal.BaseGmsClient -&gt; com.google.android.gms.common.internal.BaseGmsClient:
      ...
      344:344:void zza(com.google.android.gms.common.internal.BaseGmsClient,int,android.os.IInterface) -&gt; zza
      ...
      350:350:void zza(com.google.android.gms.common.internal.BaseGmsClient,int,android.os.IInterface) -&gt; zza
  </code></pre>
  
  <ol>
  <li>Weirdly not happening on a basic app compile. Not sure why R8 is doing anything w/ test code.</li>
  <li>Is this an R8 issue or Play Services issue?</li>
  <li>How can I resolve this. A gradle clean + invalidate/restart didn't do anything, nor did manually deleting and regenerating the mappings.txt file.</li>
  </ol>