[js, neko, lua] Fix createEmptyInstance of String

std/js/_std/Type.hx

@@ -94,6 +94,8 @@ enum ValueType {
 	}
 
 	public static inline function createEmptyInstance<T>(cl:Class<T>):T {
+		if (String == cast cl)
+			return cast "";
 		return js.lib.Object.create((cast cl).prototype);
 	}
 

std/lua/_std/Type.hx

@@ -91,10 +91,11 @@ enum ValueType {
 			return __new__(cl, lua.TableTools.unpack(cast args, 0));
 		}
 
-	public static function createEmptyInstance<T>(cl:Class<T>):T
-		untyped {
-			return _hx_new(cl.prototype);
-		}
+	public static function createEmptyInstance<T>(cl:Class<T>):T {
+		if (String == cast cl)
+			return cast "";
+		return untyped _hx_new(cl.prototype);
+	}
 
 	public static function createEnum<T>(e:Enum<T>, constr:String, ?params:Array<Dynamic>):T {
 		var f:Dynamic = Reflect.field(e, constr);

std/neko/_std/Type.hx

@@ -111,6 +111,8 @@ enum ValueType {
 	}
 
 	public static function createEmptyInstance<T>( cl : Class<T> ) : T untyped {
+		if (String == cast cl)
+			return cast "";
 		var o = __dollar__new(null);
 		__dollar__objsetproto(o,cl.prototype);
 		return o;

tests/unit/src/unit/teststd/TestType.hx

@@ -68,7 +68,7 @@ class TestType extends unit.Test {
 		//eq(t.b, "bar");
 
 		// createEmptyInstance
-		//eq(Type.createEmptyInstance(String),"foo");
+		eq(Type.createEmptyInstance(String),"");
 		//eq(Type.createEmptyInstance(null, []), null);
 		var c = Type.createEmptyInstance(ClassWithCtorDefaultValues);
 		eq(c.a, null);