Regexp parser: reset flag after scanning ahead for capture groups.

Regexp parser: reset flag after scanning ahead for capture groups.

When the regexp pattern parser encounters an unbound reference to a
capturing group, it needs to scan ahead to decide whether it really
is a reference.  The scan advances to the end of the pattern string
and sets has_more_ to false, but fails to reset it to true so that
later on, parsing a character class wrongly fails.

R=ulan@chromium.org
BUG=v8:2690
Committed: https://code.google.com/p/v8/source/detail?r=14817

[ulan, 2013-05-27 10:52:56]

lgtm

[Yang, 2013-05-27 10:53:43]

Committed patchset #1 manually as r14817 (presubmit successful).