Update on "[ET-VK][ez] Fix partitioner logic of finding keepdim arg of reduce ops"

Title says it all. For reduce ops, their signature are not all alike so some extra legwork needs to be done to identify specific arguments that need to be checked.

Also included a small update to partitioner logging to improve debuggability.

Differential Revision: [D80741737](https://our.internmc.facebook.com/intern/diff/D80741737/)

[ghstack-poisoned]

Author: ssjia