Simplify scanner and generate better error message for legacy octals in templates

src/messages.js

 // Copyright 2012 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 kMessages = {
   // Error
   cyclic_proto:                  ["Cyclic __proto__ value"],
   code_gen_from_strings:         ["%0"],
@@ skipping 136 matching lines @@
   object_not_extensible:         ["Can't add property ", "%0", ", object is not extensible"],
   illegal_access:                ["Illegal access"],
   static_prototype:              ["Classes may not have static property named prototype"],
   strict_mode_with:              ["Strict mode code may not include a with statement"],
   strict_eval_arguments:         ["Unexpected eval or arguments in strict mode"],
   too_many_arguments:            ["Too many arguments in function call (only 65535 allowed)"],
   too_many_parameters:           ["Too many parameters in function definition (only 65535 allowed)"],
   too_many_variables:            ["Too many variables declared (only 4194303 allowed)"],
   strict_param_dupe:             ["Strict mode function may not have duplicate parameter names"],
   strict_octal_literal:          ["Octal literals are not allowed in strict mode."],
+  template_octal_literal:        ["Octal literals are not allowed in template strings."],
   strict_duplicate_property:     ["Duplicate data property in object literal not allowed in strict mode"],
   accessor_data_property:        ["Object literal may not have data and accessor property with the same name"],
   accessor_get_set:              ["Object literal may not have multiple get/set accessors with the same name"],
   strict_delete:                 ["Delete of an unqualified identifier in strict mode."],
   strict_delete_property:        ["Cannot delete property '", "%0", "' of ", "%1"],
   strict_const:                  ["Use of const in strict mode."],
   strict_function:               ["In strict mode code, functions can only be declared at top level or immediately within another function." ],
   strict_read_only_property:     ["Cannot assign to read only property '", "%0", "' of ", "%1"],
   strict_cannot_assign:          ["Cannot assign to read only '", "%0", "' in strict mode"],
   strict_poison_pill:            ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
@@ skipping 1150 matching lines @@
 function SetUpStackOverflowBoilerplate() {
   var boilerplate = MakeRangeError('stack_overflow', []);
 
   %DefineAccessorPropertyUnchecked(
       boilerplate, 'stack', StackTraceGetter, StackTraceSetter, DONT_ENUM);
 
   return boilerplate;
 }
 
 var kStackOverflowBoilerplate = SetUpStackOverflowBoilerplate();