Revert: REF: do length-checks in boilerplate decorator
closes #34123 

As discussed in #34123 
let's revert this PR34081 first since it has potentially big impact on some cases in ops.

cc @jbrockmendel @jorisvandenbossche 
Hello @charlesdong1991! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:































There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2020-05-15 09:02:38 UTC small request, otherwise LGTM Can you add test(s) for the behavior that was broken in #34081 emm, something might have changed alongside, now after this revert pr, 
```python
>>> pd.Index([('a', 'b'), ('b', 'c'), ('c', 'a')]) == ('c', 'a')
array([False, False, False])
```
it returns all False.

@jbrockmendel any idea which PR recently merged could influence this? emm, not sure how on earth i could run get `array([False, False, True])` result that day, cannot replicate anymore. but seems since 1.0 or later this case returns `array([False, False, False])`  which i feel is wrong as well as a warning from numpy. i put some comments and todo there and pls let me know if it is appropriate

i could create a new issue to address this if you think is necessary. @charlesdong1991 I was also quite sure that I saw the correct behaviour in one of my environments, but also don't know where anymore.

Now, looking at it on 1.0.3, the problem is that it is creating a MultiIndex, and not a plain index with tuples in it. Ensuring we get an Index, I actually get the correct behaviour:

```
In [14]: pd.Index([('a', 'b'), ('b', 'c'), ('c', 'a')], tupleize_cols=False) == ('c', 'a') 
Out[14]: array([False, False,  True])
```

(and this example also actually fails on master) yeah, indeed, the issue i saw is that in such case, it automatically recognises as a MI, not Index. 

@jorisvandenbossche thanks very much, I will add `tupleize_cols=False` in the test to get the correct result and I will also create an issue to report this case.
 LGTM thanks @charlesdong1991 

can you open a new issue to re-implement this (e.g. essentially a cleanup to revert the revert with appropriate changes). ref #34233 

cc. @jreback 