Remove all harmony runtime flags which shipped in M51

test/mjsunit/harmony/unicode-regexp-zero-length.js

-// Copyright 2016 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.
-
-// Flags: --harmony-unicode-regexps
-
-var L = "\ud800";
-var T = "\udc00";
-var x = "x";
-
-var r = /()/g;  // Global, but not unicode.
-// Zero-length matches do not advance lastIndex.
-assertEquals(["", ""], r.exec(L + T + L + T));
-assertEquals(0, r.lastIndex);
-r.lastIndex = 1;
-assertEquals(["", ""], r.exec(L + T + L + T));
-assertEquals(1, r.lastIndex);
-
-var u = /()/ug;  // Global and unicode.
-// Zero-length matches do not advance lastIndex.
-assertEquals(["", ""], u.exec(L + T + L + T));
-assertEquals(0, u.lastIndex);
-u.lastIndex = 1;
-assertEquals(["", ""], u.exec(L + T + L + T));
-assertEquals(0, u.lastIndex);
-
-// However, with repeating matches, lastIndex does not matter.
-// We do advance from match to match.
-r.lastIndex = 2;
-assertEquals(x + L + x + T + x + L + x + T + x,
-             (L + T + L + T).replace(r, "x"));
-
-// With unicode flag, we advance code point by code point.
-u.lastIndex = 3;
-assertEquals(x + L + T + x + L + T + x,
-             (L + T + L + T).replace(u, "x"));
-
-// Test that exhausting the global match cache is fine.
-assertEquals((x + L + T).repeat(1000) + x,
-             (L + T).repeat(1000).replace(u, "x"));
-
-// Same thing for RegExp.prototype.match.
-r.lastIndex = 1;
-assertEquals(["","","","",""], (L + T + L + T).match(r));
-r.lastIndex = 2;
-assertEquals(["","","","",""], (L + T + L + T).match(r));
-
-u.lastIndex = 1;
-assertEquals(["","",""], (L + T + L + T).match(u));
-u.lastIndex = 2;
-assertEquals(["","",""], (L + T + L + T).match(u));
-
-var expected = [];
-for (var i = 0; i <= 1000; i++) expected.push("");
-assertEquals(expected, (L + T).repeat(1000).match(u));
-
-// Also test RegExp.prototype.@@split.
-assertEquals(["\u{12345}"], "\u{12345}".split(/(?:)/u));