Fix bug zloirock#463

The minifier correctly inlines an overwritten function, leading to a call
stack overflow error. This commit refactors the code a bit to prevent
the mifnier from inlining that variable.

client/core.js

@@ -6471,7 +6471,7 @@ var SUPPORTS_Y = !!(function () { try { return new RegExp('x', 'y'); } catch (e)
 
 // @@split logic
 __webpack_require__(62)('split', 2, function (defined, SPLIT, $split, maybeCallNative) {
- var internalSplit = $split;
+ var internalSplit;
  if (
  'abbc'[$SPLIT](/(b)*/)[1] == 'c' ||
  'test'[$SPLIT](/(?:)/, -1)[LENGTH] != 4 ||
@@ -6517,6 +6517,8 @@ __webpack_require__(62)('split', 2, function (defined, SPLIT, $split, maybeCallN
  internalSplit = function (separator, limit) {
  return separator === undefined && limit === 0 ? [] : $split.call(this, separator, limit);
  };
+ } else {
+ internalSplit = $split;
  }
 
  return [