Fail to use "==" operation between different types

[acphile]

for example

import mxnet as mx
mx.npx.set_np()
mx.np.arange(5)
array([0., 1., 2., 3., 4.])
b=mx.np.arange(5)
a=b.astype('int32')
a==b

it will raise Error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ubuntu/incubator-mxnet/python/mxnet/numpy/multiarray.py", line 991, in __eq__
    return equal(self, other)
  File "/home/ubuntu/incubator-mxnet/python/mxnet/numpy/multiarray.py", line 8451, in equal
    return _mx_nd_np.equal(x1, x2, out)
  File "/home/ubuntu/incubator-mxnet/python/mxnet/ndarray/numpy/_op.py", line 6622, in equal
    return _api_internal.equal(x1, x2, out)
  File "/home/ubuntu/incubator-mxnet/python/mxnet/_ffi/_ctypes/function.py", line 115, in __call__
    raise get_last_ffi_error()
mxnet.base.MXNetError: MXNetError: Type inconsistent, Provided = float32, inferred type = int32

But numpy supports "==" operation between different types

[yzhliu]

@BenjaminCHEN2016 will be helping after #18277 is merged.