add all frontend files

node_modules/es-abstract/2020/BigInt/multiply.js

@@ -0,0 +1,14 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+// https://262.ecma-international.org/11.0/#sec-numeric-types-bigint-multiply
+
+module.exports = function BigIntMultiply(x, y) {
+	if (typeof x !== 'bigint' || typeof y !== 'bigint') {
+		throw new $TypeError('Assertion failed: `x` and `y` arguments must be BigInts');
+	}
+
+	// shortcut for the actual spec mechanics
+	return x * y;
+};