Removed api call that will break the upcoming thread checking scheme

BUG=webrtc:5099

Review URL: https://codereview.webrtc.org/1472173003

Cr-Commit-Position: refs/heads/master@{#10799}
diff --git a/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc b/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
index bccccf4..a440a76 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
@@ -828,7 +828,6 @@
         ASSERT_EQ(AudioProcessing::Error::kNoError,
                   apm_->set_stream_delay_ms(30));
         apm_->set_stream_key_pressed(true);
-        apm_->set_output_will_be_muted(true);
         apm_->set_delay_offset_ms(15);
         EXPECT_EQ(apm_->delay_offset_ms(), 15);
         EXPECT_GE(apm_->num_reverse_channels(), 0);
@@ -837,7 +836,6 @@
         ASSERT_EQ(AudioProcessing::Error::kNoError,
                   apm_->set_stream_delay_ms(50));
         apm_->set_stream_key_pressed(false);
-        apm_->set_output_will_be_muted(false);
         apm_->set_delay_offset_ms(20);
         EXPECT_EQ(apm_->delay_offset_ms(), 20);
         apm_->delay_offset_ms();