fix: only warn once about WeakRef.clear() deprecation. (#140)

Author: rigor789

NativeScript/runtime/WeakRef.cpp

@@ -9,8 +9,13 @@ void WeakRef::Init(Local<Context> context) {
     Isolate* isolate = context->GetIsolate();
 
     std::string source = R"(
-        global.WeakRef.prototype.get = global.WeakRef.prototype.deref; 
+        global.WeakRef.prototype.get = global.WeakRef.prototype.deref;
+        global.WeakRef.prototype.__hasWarnedAboutClear = false;
         global.WeakRef.prototype.clear = () => {
+            if(global.WeakRef.prototype.__hasWarnedAboutClear) {
+                return;
+            }
+            global.WeakRef.prototype.__hasWarnedAboutClear = true;
             console.warn('WeakRef.clear() is non-standard and has been deprecated. It does nothing and the call can be safely removed.');
         }
     )";