Fix typo in power_double_double

Contributed by net147@gmail.com

BUGS=
TEST=mjsunit/math-pow,mjsunit/math-sqrt

Review URL: https://chromiumcodereview.appspot.com/10116001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11363 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/assembler.cc

@@ -1163,7 +1163,7 @@ double power_double_double(double x, double y) {
 
   if (x == 2.0) {
     int y_int = static_cast<int>(y);
-    if (y == y_int) return ldexp(1.0, y);
+    if (y == y_int) return ldexp(1.0, y_int);
   }
 #endif