Fix induction variable type in scf.for py binding.

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

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D159534

mlir/python/mlir/dialects/_scf_ops_ext.py

@@ -52,7 +52,7 @@ class ForOp:
                 ip=ip,
             )
         )
-        self.regions[0].blocks.append(IndexType.get(), *results)
+        self.regions[0].blocks.append(self.operands[0].type, *results)
 
     @property
     def body(self):