Fix tokenizer's bracket pairs' open stack

[redapple]

I found this bug while parsing things like:

for (index in [1,2,3]) /^salign$/i.test('salign')

(from rspivak/slimit#54)

Before the fix, you get:

for (index in [1, 2, 3]) / ^ salign$ / i.test('salign')

The regular expression is not detected.

With this fix, the regular expression literal is kept as-is:

>>> import jsbeautifier
>>> print jsbeautifier.beautify("for (index in [1,2,3]) /^salign$/i.test('salign')")
for (index in [1,2,3]) /^salign$/i.test('salign')
>>> 

[bitwiseman]

Strange symptom. Good catch on the fix though, thanks!