fix: check if a static method is already set (#122)

Author: darind

NativeScript/runtime/MetadataBuilder.mm

@@ -526,8 +526,10 @@
 
             DefineFunctionLengthProperty(context, methodMeta->encodings(), staticMethod);
 
-            bool success = ctorFunc->Set(context, tns::ToV8String(isolate, methodMeta->jsName()), staticMethod).FromMaybe(false);
-            tns::Assert(success, isolate);
+            if (!ctorFunc->Has(context, tns::ToV8String(isolate, methodMeta->jsName())).FromJust()) {
+                bool success = ctorFunc->Set(context, tns::ToV8String(isolate, methodMeta->jsName()), staticMethod).FromMaybe(false);
+                tns::Assert(success, isolate);
+            }
 
             names.emplace(methodName, 0);
         }