Revert of [parser] Forbid \08 in strict strings

test/mjsunit/es6/templates.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var num = 5;
 var str = "str";
 function fn() { return "result"; }
 var obj = {
   num: num,
   str: str,
@@ skipping 458 matching lines @@
 
   {
     // block
   }`jkl`;
 })();
 
 
 (function testLegacyOctal() {
   assertEquals('\u0000', `\0`);
   assertEquals('\u0000a', `\0a`);
-  for (var i = 0; i < 10; i++) {
+  for (var i = 0; i < 8; i++) {
     var code = "`\\0" + i + "`";
     assertThrows(code, SyntaxError);
     code = "(function(){})" + code;
     assertThrows(code, SyntaxError);
   }
 
   assertEquals('\\0', String.raw`\0`);
 })();
 
 
 (function testSyntaxErrorsNonEscapeCharacter() {
   assertThrows("`\\x`", SyntaxError);
   assertThrows("`\\u`", SyntaxError);
   for (var i = 1; i < 8; i++) {
     var code = "`\\" + i + "`";
     assertThrows(code, SyntaxError);
     code = "(function(){})" + code;
     assertThrows(code, SyntaxError);
   }
 })();
 
 
 (function testValidNumericEscapes() {
   assertEquals("8", `\8`);
   assertEquals("9", `\9`);
+  assertEquals("\u00008", `\08`);
+  assertEquals("\u00009", `\09`);
 })();
 
 
 (function testLegacyOctalEscapesInExpressions() {
   // Allowed in sloppy expression
   assertEquals("\x07", `${"\07"}`);
 
   // Disallowed in template tail
   assertThrows("`${\"\\07\"}\\07`", SyntaxError);
 
@@ skipping 192 matching lines @@
   assertSame(result, f());
 })();
 
 
 (function testEvalTagSloppy() {
   var f = (x) => eval`a${x}b`;
   var result = f();
   assertEquals(["a", "b"], result);
   assertSame(result, f());
 })();