Added a workaround for a UC Browser specific version bug with unobservable RegExp#sticky flag

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Changelog
 ##### Unreleased
+- Added a workaround for a UC Browser specific version bug with unobservable `RegExp#sticky` flag, [#1008](https://github.com/zloirock/core-js/issues/1008), [#1015](https://github.com/zloirock/core-js/issues/1015)
 - Added handling of comments and specific spaces to `Function#name` polyfill, [#1010](https://github.com/zloirock/core-js/issues/1010), thanks [@ildar-shaimordanov](https://github.com/ildar-shaimordanov)
 - Updated Deno compat data mapping
 - Added iOS Safari 15.2 compat data mapping

packages/core-js/internals/regexp-exec.js

@@ -28,7 +28,7 @@ var UPDATES_LAST_INDEX_WRONG = (function () {
   return re1.lastIndex !== 0 || re2.lastIndex !== 0;
 })();
 
-var UNSUPPORTED_Y = stickyHelpers.UNSUPPORTED_Y || stickyHelpers.BROKEN_CARET;
+var UNSUPPORTED_Y = stickyHelpers.BROKEN_CARET;
 
 // nonparticipating capturing group, copied from es5-shim's String#split patch.
 var NPCG_INCLUDED = /()??/.exec('')[1] !== undefined;

packages/core-js/internals/regexp-sticky-helpers.js

@@ -4,15 +4,27 @@ var global = require('../internals/global');
 // babel-minify and Closure Compiler transpiles RegExp('a', 'y') -> /a/y and it causes SyntaxError
 var $RegExp = global.RegExp;
 
-exports.UNSUPPORTED_Y = fails(function () {
+var UNSUPPORTED_Y = fails(function () {
   var re = $RegExp('a', 'y');
   re.lastIndex = 2;
   return re.exec('abcd') != null;
 });
 
-exports.BROKEN_CARET = fails(function () {
+// UC Browser bug
+// https://github.com/zloirock/core-js/issues/1008
+var MISSED_STICKY = UNSUPPORTED_Y || fails(function () {
+  return !$RegExp('a', 'y').sticky;
+});
+
+var BROKEN_CARET = UNSUPPORTED_Y || fails(function () {
   // https://bugzilla.mozilla.org/show_bug.cgi?id=773687
   var re = $RegExp('^r', 'gy');
   re.lastIndex = 2;
   return re.exec('str') != null;
 });
+
+module.exports = {
+  BROKEN_CARET: BROKEN_CARET,
+  MISSED_STICKY: MISSED_STICKY,
+  UNSUPPORTED_Y: UNSUPPORTED_Y
+};

packages/core-js/modules/es.regexp.constructor.js

@@ -38,10 +38,11 @@ var re2 = /a/g;
 // "new" should create a new object, old webkit bug
 var CORRECT_NEW = new NativeRegExp(re1) !== re1;
 
+var MISSED_STICKY = stickyHelpers.MISSED_STICKY;
 var UNSUPPORTED_Y = stickyHelpers.UNSUPPORTED_Y;
 
 var BASE_FORCED = DESCRIPTORS &&
-  (!CORRECT_NEW || UNSUPPORTED_Y || UNSUPPORTED_DOT_ALL || UNSUPPORTED_NCG || fails(function () {
+  (!CORRECT_NEW || MISSED_STICKY || UNSUPPORTED_DOT_ALL || UNSUPPORTED_NCG || fails(function () {
     re2[MATCH] = false;
     // RegExp constructor can alter flags and IsRegExp works correct with @@match
     return NativeRegExp(re1) != re1 || NativeRegExp(re2) == re2 || NativeRegExp(re1, 'i') != '/a/i';
@@ -146,9 +147,9 @@ if (isForced('RegExp', BASE_FORCED)) {
 
     rawFlags = flags;
 
-    if (UNSUPPORTED_Y && 'sticky' in re1) {
+    if (MISSED_STICKY && 'sticky' in re1) {
       sticky = !!flags && stringIndexOf(flags, 'y') > -1;
-      if (sticky) flags = replace(flags, /y/g, '');
+      if (sticky && UNSUPPORTED_Y) flags = replace(flags, /y/g, '');
     }
 
     if (UNSUPPORTED_NCG) {

packages/core-js/modules/es.regexp.sticky.js

@@ -1,6 +1,6 @@
 var global = require('../internals/global');
 var DESCRIPTORS = require('../internals/descriptors');
-var UNSUPPORTED_Y = require('../internals/regexp-sticky-helpers').UNSUPPORTED_Y;
+var MISSED_STICKY = require('../internals/regexp-sticky-helpers').MISSED_STICKY;
 var classof = require('../internals/classof-raw');
 var defineProperty = require('../internals/object-define-property').f;
 var getInternalState = require('../internals/internal-state').get;
@@ -10,7 +10,7 @@ var TypeError = global.TypeError;
 
 // `RegExp.prototype.sticky` getter
 // https://tc39.es/ecma262/#sec-get-regexp.prototype.sticky
-if (DESCRIPTORS && UNSUPPORTED_Y) {
+if (DESCRIPTORS && MISSED_STICKY) {
   defineProperty(RegExpPrototype, 'sticky', {
     configurable: true,
     get: function () {