Fix FY5253 onOffset/apply bug, simplify
Similar to #18875.

The actual bugfix here is just changing the comparison in `apply` from `other < whatever` to `norm < whatever`.  The remaining edits to `get_year_end` are orthogonal simplification (which I guess could go in a separate PR).

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

That should be the last new one for a while...  I hope. Close was accidental. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=h1) Report
> Merging [#18877](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/80a5399e59f409749f08f2f38903e25b1c92d5e0?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18877/graphs/tree.svg?height=150&width=650&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18877      +/-   ##
==========================================
- Coverage   91.59%   91.57%   -0.02%     
==========================================
  Files         150      150              
  Lines       48924    48911      -13     
==========================================
- Hits        44813    44792      -21     
- Misses       4111     4119       +8
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.94% <100%> (-0.02%)` | :arrow_down: |
| #single | `41.17% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/18877/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `97.07% <100%> (+0.28%)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/18877/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.22% <0%> (-1.74%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=footer). Last update [80a5399...9f02521](https://codecov.io/gh/pandas-dev/pandas/pull/18877?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Ping This is a blocker for addressing bugs in FY5253Quarter. lgtm. conflict in whatsnew. ping when pushed / green. ping thanks!