Various compatibility issues in String.prototype.split()

"aa".split(undefined,0).length
=> should return 0 instead of 1

"aa".split(/(a)/, 1).length
=> should return 1 instead of 2

"abc".split("", 1).length
=> should return 1 instead of 3

"aa".split((r = /a/, r.lastIndex = {valueOf:function(){throw 2}}, r))
=> should not throw an exception