[FeatureRequest]MXNet Split operator to support variable length splits

[Roshrini]

Description

MXNet's split operator only support equal splits of a tensor according to http://mxnet.incubator.apache.org/api/python/symbol/symbol.html#mxnet.symbol.split

This issue is to request the support for variable length splits.
For example:

input = mx.nd.array([1., 2., 3., 4., 5., 6.])
mx.nd.split(input, axis=0, num_outputs=[2,4]) # mayebe accepting num_outputs as a list 
expected_output = [
 [1. 2.]
 <NDArray 2 @cpu(0)>, 
[ [3. 4. 5. 6.]
 <NDArray 4 @cpu(0)>]

[nswamy]

Closing as the PR fixes.

[MoritzMaxeiner]

@nswamy Why was this feature request closed? The requested feature is not available in 1.2 release or master AFAICT - I could not find any PR fixing this.