upgrade to JUCE 5.4.3. Remove (probably) unused JUCE modules. Remove VST2 target (it's been end-of-life'd by Steinberg and by JUCE)

modules/juce_audio_utils/gui/juce_AudioThumbnail.cpp

@@ -98,7 +98,7 @@ public:
     {
     }
 
-    ~LevelDataSource()
+    ~LevelDataSource() override
     {
         owner.cache.getTimeSliceThread().removeTimeSliceClient (this);
     }
@@ -642,7 +642,7 @@ void AudioThumbnail::saveTo (OutputStream& output) const
 //==============================================================================
 bool AudioThumbnail::setDataSource (LevelDataSource* newSource)
 {
-    jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());
+    JUCE_ASSERT_MESSAGE_MANAGER_IS_LOCKED
 
     numSamplesFinished = 0;