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

test/mjsunit/regress/regress-2690.js

Index: test/mjsunit/regress/regress-2690.js
diff --git a/test/mjsunit/regress/regress-crbug-172345.js b/test/mjsunit/regress/regress-2690.js
similarity index 94%
copy from test/mjsunit/regress/regress-crbug-172345.js
copy to test/mjsunit/regress/regress-2690.js
index 711501caa791f2974635ac4dd894568a2e3fc982..5fe7dc42dc693cf7f0a3e9a2b13c0f7b306189e2 100644
--- a/test/mjsunit/regress/regress-crbug-172345.js
+++ b/test/mjsunit/regress/regress-2690.js
@@ -25,10 +25,5 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-function f(a,i) {
-  return a[i];
-}
+assertTrue(/\1[a]/.test("\1a"));
 
-f([1,2,3], "length");
-f([1,2,3], "length");
-f([1,2,3], 2);