LibJS: Replace usages of JS_{DECLARE, DEFINE}_NATIVE_GETTER

These macros are equivalent to JS_{DECLARE, DEFINE}_NATIVE_FUNCTION and
were only sometimes used, so let's just get rid of them altogether.

Userland/Libraries/LibJS/Runtime/RegExpConstructor.h

@@ -24,7 +24,7 @@ public:
 private:
     virtual bool has_constructor() const override { return true; }
 
-    JS_DECLARE_NATIVE_GETTER(symbol_species_getter);
+    JS_DECLARE_NATIVE_FUNCTION(symbol_species_getter);
 };
 
 }