Fix induction variable type in scf.for py binding.

[bythew3i]

Summary

• make sure that the type of induction variable should be determined by the type of the lower bound type.

mlir/python/mlir/dialects/_scf_ops_ext.py

):
                 operands=[
                     _get_op_result_or_value(o) for o in [lower_bound, upper_bound, step]
                 ]
                 + list(iter_args),
                 loc=loc,
                 ip=ip,
             )
         )
-        self.regions[0].blocks.append(IndexType.get(), *results)
+        self.regions[0].blocks.append(self.operands[0].type, *results)
 
     @property
     def body(self):
         """Returns the body (block) of the loop."""
         return self.regions[0].blocks[0]
 
     @property
     def induction_variable(self):