Update base for Update on "[Executorch] mul broadcast update"

Handle broadcast for > 2D tensors in optimized library. For now broadcast
across only non 0th and (N-1)st dim is supported in optimized path.

Differential Revision: [D64156862](https://our.internmc.facebook.com/intern/diff/D64156862/)

[ghstack-poisoned]

Author: kimishpatel