Function addExtendsHelperIfNeeded

test/fixtures/snapshot/typescript.js:99048–99053

* Adds a call to the `__extends` helper if needed for a class. * * @param statements The statements of the class body function. * @param node The ClassExpression or ClassDeclaration node. * @param extendsClauseElement The expression for the class `extends` clause.

(statements, node, extendsClauseElement)

         * @param extendsClauseElement The expression for the class `extends` clause.
         */
        function addExtendsHelperIfNeeded(statements, node, extendsClauseElement) {
            if (extendsClauseElement) {
                statements.push(ts.setTextRange(factory.createExpressionStatement(emitHelpers().createExtendsHelper(factory.getInternalName(node))), 
                /*location*/ extendsClauseElement));
            }
        }
        /**
         * Adds the constructor of the class to a class body function.
         *