message: reduce num_outputs in parallel map test
diff: @@ -1582,7 +1582,7 @@ class ParallelMapDatasetCheckpointTest(checkpoint_test_base.CheckpointTestBase,
  @combinations.generate(test_base.default_test_combinations())
  def testCaptureDefunInMapFn(self):
  - num_outputs = 100
  + num_outputs = 10
  def _build_ds():
  @@ -1597,7 +1597,7 @@ class ParallelMapDatasetCheckpointTest(checkpoint_test_base.CheckpointTestBase,
  @combinations.generate(test_base.default_test_combinations())
  def testBuildDefunInMapFn(self):
  - num_outputs = 100
  + num_outputs = 10
  def _build_ds():
  