PERF: expand asv benchmark coverage
Continuing on the approach in #23935, I've identified significant functions with no benchmark coverage in the `asv` suite - this time extending the line tracing analysis down to the Cython layer. Of interest:

- `merge_asof()` is only benchmarked in the default direction, despite the other two directions having unique Cython codepaths
- Reindex operations on a `PeriodIndex` are currently largely uncovered
- `CategoricalIndex` is missing a lot of basic cases
- There's a chunk of Cython code specifically for parsing `Quarter` strings that now has a benchmark
 - Several typos in the `Timestamp` benchmarks

I'll update this comment when the `asv` comparison runs complete.

- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
