Update base for Update on "[ET-VK] Splitting TILE_SIZE to TILE_SIZE_X and TILE_SIZE_Y in conv2d pw."

This diff splits the `TILE_SIZE` variable in the `conv2d_pw` GLSL code into `TILE_SIZE_X` and `TILE_SIZE_Y`. This change is made so tile size in different dimensions can be tuned separately.

Differential Revision: [D68400783](https://our.internmc.facebook.com/intern/diff/D68400783/)

[ghstack-poisoned]

Author: trivedivivek