CI: Moving 3 jobs from travis to azure
We currently have 8 jobs in travis, and 7 jobs in azure. But in azure we've got 30 concurrent jobs, and in travis 15, making travis our bottleneck.

Here I move 3 jobs from travis to azure, so we have 10 in travis, and 5 in azure. This should keep things balanced for now, and both CI systems should more or less be synchronized.

I moved the 3 jobs that don't run the db tests (we don't have mysql or postgres in azure at the moment), and left in travis the ones that do use the db, and the two "allow failures" ones.


# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=h1) Report
> Merging [#24460](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/aa1549f7fd8ce81bf23296bf92fe9713aa8d6e20?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24460/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24460   +/-   ##
=======================================
  Coverage    92.3%    92.3%           
=======================================
  Files         163      163           
  Lines       51969    51969           
=======================================
  Hits        47968    47968           
  Misses       4001     4001
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.7% <ø> (ø)` | :arrow_up: |
| #single | `43.01% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24460?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/24460?src=pr&el=footer). Last update [aa1549f...b66a11a](https://codecov.io/gh/pandas-dev/pandas/pull/24460?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/24460?src=pr&el=h1) Report
> Merging [#24460](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/aa1549f7fd8ce81bf23296bf92fe9713aa8d6e20?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24460/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24460   +/-   ##
=======================================
  Coverage    92.3%    92.3%           
=======================================
  Files         163      163           
  Lines       51969    51969           
=======================================
  Hits        47968    47968           
  Misses       4001     4001
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.7% <ø> (ø)` | :arrow_up: |
| #single | `43.01% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24460?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/24460?src=pr&el=footer). Last update [aa1549f...b0383c8](https://codecov.io/gh/pandas-dev/pandas/pull/24460?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 lgtm ping on green. thanks @datapythonista 