Revert "Fix a memory leak in ExpressionParser.cpp"

This reverts commit cce809ac90.

The code was actually correct: "expr" is never allocated when an error is
returned. This means when the expression parser fails, deleting "expr" means
deleting an uninitialized pointer.

Source/Core/InputCommon/Src/ControllerInterface/ExpressionParser.cpp

@@ -549,10 +549,7 @@ ExpressionParseStatus ParseExpressionInner(std::string str, ControlFinder &finde
 	Parser p(tokens, finder);
 	status = p.Parse(&expr);
 	if (status != EXPRESSION_PARSE_SUCCESS)
-	{
-		delete expr;
 		return status;
-	}
 
 	*expr_out = expr;
 	return EXPRESSION_PARSE_SUCCESS;