AUv3: Avoid calling setFullState: on the superclass during state restoration

On some platforms, the superclass implementation can throw if it detects
that the preset data is malformed, but it's not clear exactly how the
system determines this.

We now apply only the JUCE state.

modules/juce_audio_plugin_client/juce_audio_plugin_client_AUv3.mm

@@ -245,16 +245,8 @@ public:
 
         if (state.getSize() > 0)
         {
-            NSData* ourState = [[NSData alloc] initWithBytes: state.getData()
-                                                      length: state.getSize()];
-
-            NSString* nsKey = [[NSString alloc] initWithUTF8String: JUCE_STATE_DICTIONARY_KEY];
-
-            [retval setObject: ourState
-                       forKey: nsKey];
-
-            [nsKey    release];
-            [ourState release];
+            [retval setObject: [[NSData alloc] initWithBytes: state.getData() length: state.getSize()]
+                       forKey: @JUCE_STATE_DICTIONARY_KEY];
         }
 
         return [retval autorelease];
@@ -265,39 +257,26 @@ public:
         if (state == nullptr)
             return;
 
-        NSMutableDictionary<NSString*, id>* modifiedState = [[NSMutableDictionary<NSString*, id> alloc] init];
-        [modifiedState addEntriesFromDictionary: state];
+        NSObject* obj = [state objectForKey: @JUCE_STATE_DICTIONARY_KEY];
 
-        NSString* nsPresetKey = [[NSString alloc] initWithUTF8String: kAUPresetDataKey];
-        [modifiedState removeObjectForKey: nsPresetKey];
-        [nsPresetKey release];
+        if (obj == nullptr || ! [obj isKindOfClass: [NSData class]])
+            return;
 
-        ObjCMsgSendSuper<AUAudioUnit, void> (au, @selector (setFullState:), state);
+        auto* data = reinterpret_cast<NSData*> (obj);
+        const auto numBytes = static_cast<int> ([data length]);
 
-        NSString* nsKey = [[NSString alloc] initWithUTF8String: JUCE_STATE_DICTIONARY_KEY];
-        NSObject* obj = [modifiedState objectForKey: nsKey];
-        [nsKey release];
+        if (numBytes <= 0)
+            return;
 
-        if (obj != nullptr)
-        {
-            if ([obj isKindOfClass:[NSData class]])
-            {
-                NSData* data = reinterpret_cast<NSData*> (obj);
-                const int numBytes = static_cast<int> ([data length]);
-                const juce::uint8* const rawBytes = reinterpret_cast< const juce::uint8* const> ([data bytes]);
+        auto* rawBytes = reinterpret_cast<const juce::uint8* const> ([data bytes]);
 
-                if (numBytes > 0)
-                {
-                   #if JUCE_AU_WRAPPERS_SAVE_PROGRAM_STATES
-                    getAudioProcessor().setCurrentProgramStateInformation (rawBytes, numBytes);
-                   #else
-                    getAudioProcessor().setStateInformation (rawBytes, numBytes);
-                   #endif
-                }
-            }
-        }
+        ScopedKeyChange scope (au, @"allParameterValues");
 
-        [modifiedState release];
+       #if JUCE_AU_WRAPPERS_SAVE_PROGRAM_STATES
+        getAudioProcessor().setCurrentProgramStateInformation (rawBytes, numBytes);
+       #else
+        getAudioProcessor().setStateInformation (rawBytes, numBytes);
+       #endif
     }
 
     AUParameterTree* getParameterTree() const