TST: Enable Index dtype comparison by default
Enable `check_index_type` and `check_columns_type`  by default to detect dtype related problems.

Fixed following 2 minor bugs at the same time, but I'm willing to split them to separate PR if required.
### 1. `Series.quantile` with empty list results in `object` index rather than `float`.

```
pd.Series([1, 2, 3]).quantile([]).index
# Index([], dtype='object')
```
### 2. `pd.merge` includes empty data may result in `Int64Index` rather than `object`

Sorry, #10826 was incomplete.

When fixing #11497, #11586, we can enable corresponding `check_index_type`

thanks!
