Over-zealous assertion fix.

modules/juce_core/containers/juce_OwnedArray.h

@@ -438,7 +438,7 @@ public:
             numElementsToAdd = arrayToAddFrom.size() - startIndex;
 
         data.ensureAllocatedSize (numUsed + numElementsToAdd);
-        jassert (data.elements != nullptr);
+        jassert (numElementsToAdd <= 0 || data.elements != nullptr);
 
         while (--numElementsToAdd >= 0)
         {