Possible memory leak in Match.exec() in 4.x branch

[SlNPacifist]

Here is current 4.x exec function:

Match.prototype.exec = function exec(context) {
  var save = this.checkDepth();
  ...
  if (i === this.count)
    return undefined;
  ...
  this.restoreDepth(save);
};

In some cases checkDepth increases this.maskOffset, but restoreDepth is not called afterwards, since no match was found.
This leads to increasing of this.maskOffset and this.mask array.

[miripiruni]

Also this fix was released in v4.4.2, v6.7.1, v7.7.4, v8.6.10.