numeric.c: short circuit

* numeric.c (int_pow): short circuit when y is 0, always return 1.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57270 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

numeric.c

@@ -3892,6 +3892,7 @@ int_pow(long x, unsigned long y)
     int neg = x < 0;
     long z = 1;
 
+    if (y == 0) return INT2FIX(1);
     if (neg) x = -x;
     if (y & 1)
 	z = x;