Suppress a memcheck error in Opus decoder

tools/valgrind-webrtc/memcheck/suppressions.txt

Index: tools/valgrind-webrtc/memcheck/suppressions.txt
diff --git a/tools/valgrind-webrtc/memcheck/suppressions.txt b/tools/valgrind-webrtc/memcheck/suppressions.txt
index d6ab8079b2b7e88a73f52aca97588649404f4034..841a639f74136bcb9fbf0cf6965752b3f4a03f55 100644
--- a/tools/valgrind-webrtc/memcheck/suppressions.txt
+++ b/tools/valgrind-webrtc/memcheck/suppressions.txt
@@ -457,3 +457,18 @@
    fun:_ZNK3rtc15CriticalSection5EnterEv
    ...
 }
+{
+   bug_6444
+   Memcheck:Unaddressable
+   fun:pitch_search
+   fun:run_prefilter
+   fun:celt_encode_with_ec
+   fun:opus_encode_native
+   fun:opus_encode
+   fun:WebRtcOpus_Encode
+   fun:_ZN6webrtc16AudioEncoderOpus10EncodeImplEjN3rtc9ArrayViewIKsEEPNS1_7BufferTIhEE
+   fun:_ZN6webrtc12AudioEncoder6EncodeEjN3rtc9ArrayViewIKsEEPNS1_7BufferTIhEE
+   fun:_ZN6webrtc16AudioDecoderTest11EncodeFrameEPKsmPN3rtc7BufferTIhEE
+   fun:_ZN6webrtc16AudioDecoderTest16EncodeDecodeTestEmidii
+   fun:_ZN6webrtc44AudioDecoderOpusStereoTest_EncodeDecode_Test8TestBodyEv
+}