BUG: fix construction from read-only non-ns datetime64 numpy array
Closes #34843
Travis failure are the numpy dev warnings > we typically also call this klass 

There are several existing occurrences of a "constructor" fixture, already

> and don’t much care about dataframe-dict here

We actually do, as the test above has an xfail because `DataFrame(dict)` vs `DataFrame(array)` behaves differently (the sanitization of datetime64 values follows a different code path in both cases). 
In this case both work, but so I think it is good to test both.

> creating this fixture for a single use is not that great

Yeah, that is because I first wanted to share it with the other existing test. But because that has an xfail on one of the fixture parameters, making it difficult to share. Once that bug is fixed, it can be shared though.

 > as the test above has an xfail because DataFrame(dict) vs DataFrame(array) behaves differently (the sanitization of datetime64 values follows a different code path in both cases).

Which is https://github.com/pandas-dev/pandas/issues/26919