This was largely an AI port of https://github.com/j2kun/heir_torch_coverage to a CI workflow in HEIR directly.

Features:

0. Runs a CI testing heir-opt on all the listed torch operators every two weeks (offset for HEIR monthly release)
1. Does not depend on torch-mlir in HEIR directly, only in CI
2. Updates polynomial-approximation to choose smarter default intervals, hopefully avoiding trivial crashes of non-polynomial functions like sqrt and log2
3. Saves the failure logs to the GH action outputs so they can be inspected
4. Writes a table to the action output and to a distinguished comment in #2923