Remove all harmony runtime flags which shipped in M51

test/cctest/test-regexp.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 153 matching lines @@
 #define CHECK_SIMPLE(input, simple) CHECK_EQ(simple, CheckSimple(input));
 #define CHECK_MIN_MAX(input, min, max)                                         \
   { MinMaxPair min_max = CheckMinMaxMatch(input);                              \
     CHECK_EQ(min, min_max.min_match);                                          \
     CHECK_EQ(max, min_max.max_match);                                          \
   }
 
 
 void TestRegExpParser(bool lookbehind) {
   FLAG_harmony_regexp_lookbehind = lookbehind;
-  FLAG_harmony_unicode_regexps = true;
 
   CHECK_PARSE_ERROR("?");
 
   CheckParseEq("abc", "'abc'");
   CheckParseEq("", "%");
   CheckParseEq("abc|def", "(| 'abc' 'def')");
   CheckParseEq("abc|def|ghi", "(| 'abc' 'def' 'ghi')");
   CheckParseEq("^xxx$", "(: @^i 'xxx' @$i)");
   CheckParseEq("ab\\b\\d\\bcd", "(: 'ab' @b [0-9] @b 'cd')");
   CheckParseEq("\\w|\\d", "(| [0-9 A-Z _ a-z] [0-9])");
@@ skipping 1839 matching lines @@
   v8::Local<v8::String> external =
       v8::String::NewExternalOneByte(isolate, new UncachedExternalString())
           .ToLocalChecked();
   CHECK(v8::Utils::OpenHandle(*external)->map() ==
         CcTest::i_isolate()->heap()->short_external_one_byte_string_map());
   v8::Local<v8::Object> global = env->Global();
   global->Set(env.local(), v8_str("external"), external).FromJust();
   CompileRun("var re = /y(.)/; re.test('ab');");
   ExpectString("external.substring(1).match(re)[1]", "z");
 }