CLN: Simplify read_csv tz offset parsing
I _think_ after  #22457  we do not need the `np.asarray` calls that were introduced in #22380
If tests pass, I'm +1 for this. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22494?src=pr&el=h1) Report
> Merging [#22494](https://codecov.io/gh/pandas-dev/pandas/pull/22494?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/55d176d1cd624f8921379c0ceed06fb8e00625b9?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/22494/graphs/tree.svg?src=pr&width=650&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/22494?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22494   +/-   ##
=======================================
  Coverage   92.04%   92.04%           
=======================================
  Files         169      169           
  Lines       50776    50776           
=======================================
  Hits        46737    46737           
  Misses       4039     4039
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <100%> (ø)` | :arrow_up: |
| #single | `42.23% <66.66%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22494?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/parsers.py](https://codecov.io/gh/pandas-dev/pandas/pull/22494/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnNlcnMucHk=) | `95.48% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22494?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/22494?src=pr&el=footer). Last update [55d176d...97e0e6b](https://codecov.io/gh/pandas-dev/pandas/pull/22494?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Looks like tests are passing besides a travis build termination.  thanks!