[regexp] Use consistent map checks for fast paths

test/mjsunit/es6/regexp-flags.js

 // Copyright 2015 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 r1 = /abc/gi;
 assertEquals("abc", r1.source);
 assertTrue(r1.global);
 assertTrue(r1.ignoreCase);
 assertFalse(r1.multiline);
 assertFalse(r1.sticky);
@@ skipping 27 matching lines @@
 assertTrue(r3.global);
 assertEquals(1, get_count);
 assertTrue(r3.ignoreCase);
 assertEquals(2, get_count);
 // Overridden flag getters affects the flags getter.
 assertEquals("gi", r3.flags);
 assertEquals(4, get_count);
 // Overridden flag getters affect string.replace
 // TODO(adamk): Add more tests here once we've switched
 // to use [[OriginalFlags]] in more cases.
-assertEquals(expected, string.replace(r3, "X"));
-assertEquals(5, get_count);
+// TODO(jgruber): This exact case actually causes an infinite loop in the spec
+// (@@replace sees global = true while BuiltinExec sees global = false).
+// Comment the test for now and remove / fix once this has been resolved on
+// the spec side.
+//assertEquals(expected, string.replace(r3, "X"));
+//assertEquals(5, get_count);
 
 
 function testName(name) {
   // Test for ES2017 RegExp web compatibility semantics
   // https://github.com/tc39/ecma262/pull/511
   assertEquals(name === "source" ? "(?:)" : undefined,
                RegExp.prototype[name]);
   assertEquals(
       "get " + name,
       Object.getOwnPropertyDescriptor(RegExp.prototype, name).get.name);
@@ skipping 50 matching lines @@
   },
   get unicode() {
     map.u = counter++;
   },
   get sticky() {
     map.y = counter++;
   }
 };
 testGenericFlags(object);
 assertEquals({ g: 0, i: 1, m: 2, u: 3, y: 4 }, map);