Fix -Wextra-semi warnings.

Starting from https://chromium-review.googlesource.com/c/1485012,
-Wextra-semi is enabled and WebRTC has some violations to fix.

This is a follow-up of https://webrtc-review.googlesource.com/c/123560.

Bug: webrtc:10355
Change-Id: I012b7497fc8991037fd77aa98f1579c22e08206f
Reviewed-on: https://webrtc-review.googlesource.com/c/124126
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26831}

modules/audio_coding/test/EncodeDecodeTest.h

@@ -65,7 +65,7 @@ class Sender {
 class Receiver {
  public:
   Receiver();
-  virtual ~Receiver() {};
+  virtual ~Receiver() {}
   void Setup(AudioCodingModule *acm, RTPStream *rtpStream,
              std::string out_file_name, size_t channels, int file_num);
   void Teardown();