fix test scatter reduce

Author: Starrysea996

test/legacy_test/test_scatter_reduce_op.py

@@ -27,7 +27,7 @@
 def scatter_reduce_net(x, axis=-1):
     index = paddle.full_like(x, fill_value=2, dtype='int64')
     n = paddle.numel(x)
-    ind = paddle.arange(n, dtype='float32')
+    ind = paddle.arange(n, dtype='int32').astype(x.dtype)
     value = paddle.reshape(ind, x.shape)
     return paddle.scatter_reduce(x, axis, index, value, reduce='sum')