BUG: DataFrame.update with tz-aware date doesn't return naive data
- [x] closes #25807
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=h1) Report
> Merging [#25810](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/fbe25233345b750031911f0d4b0845fa115c4432?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/25810/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25810   +/-   ##
=======================================
  Coverage   91.27%   91.27%           
=======================================
  Files         173      173           
  Lines       53002    53002           
=======================================
  Hits        48375    48375           
  Misses       4627     4627
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.83% <100%> (ø)` | :arrow_up: |
| #single | `41.77% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25810/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.79% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25810?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/25810?src=pr&el=footer). Last update [fbe2523...116e8dd](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=h1) Report
> Merging [#25810](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/fbe25233345b750031911f0d4b0845fa115c4432?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/25810/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25810   +/-   ##
=======================================
  Coverage   91.27%   91.27%           
=======================================
  Files         173      173           
  Lines       53002    53002           
=======================================
  Hits        48375    48375           
  Misses       4627     4627
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.83% <100%> (ø)` | :arrow_up: |
| #single | `41.77% <0%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25810/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.79% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25810?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/25810?src=pr&el=footer). Last update [fbe2523...116e8dd](https://codecov.io/gh/pandas-dev/pandas/pull/25810?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks @mroeschke 

I *think* this might close one or more outstanding  update issues (other than the OP of course)