BUG: pickle compat with UTC tz's
closes #16608

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=h1) Report
> Merging [#16611](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/bf9997520443e0a5f505f11e11f46290ea95b3a3?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16611/graphs/tree.svg?token=eZ4WkYLtcO&width=650&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #16611   +/-   ##
=======================================
  Coverage   90.93%   90.93%           
=======================================
  Files         161      161           
  Lines       49267    49267           
=======================================
  Hits        44800    44800           
  Misses       4467     4467
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.69% <100%> (ø)` | :arrow_up: |
| #single | `40.22% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/compat/pickle\_compat.py](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=tree#diff-cGFuZGFzL2NvbXBhdC9waWNrbGVfY29tcGF0LnB5) | `69.51% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16611?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/16611?src=pr&el=footer). Last update [bf99975...c7966ff](https://codecov.io/gh/pandas-dev/pandas/pull/16611?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
