Add missing specialization to int.__rshift__

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/ints/IntBuiltins.java

@@ -1185,6 +1185,12 @@ long doLL(long left, long right) {
             return left >> right;
         }
 
+        @Specialization
+        PInt doIPi(int left, PInt right) {
+            raiseNegativeShiftCount(!right.isZeroOrPositive());
+            return factory().createInt(op(BigInteger.valueOf(left), right.intValue()));
+        }
+
         @Specialization
         PInt doLPi(long left, PInt right) {
             raiseNegativeShiftCount(!right.isZeroOrPositive());