Promote broadcast logic from TensorFlowLite to Dialect/ directory

We also need the broadcast logic in the TensorFlow dialect. Move it to a
Dialect/ directory for a broader scope. This Dialect/ directory is intended
for code not in core IR, but can potentially be shared by multiple dialects.

Apart from fixing TensorFlow op TableGen to use this trait, this CL only
contains mechanical code shuffling.

PiperOrigin-RevId: 229563911