vector distribution tests should test with vectors of not all the same values

[bbbales2]

Description

There was a bug in an lcdf distribution that would have been caught if the vectorized versions of the CDFs were tested with vectors of different values (#1662).

Right now the vectorized tests build vectors of the same value (see the repeat_as_vector test).

This would have been caught if there was a test that tested vectorized vs. non-vectorized versions of the functions where it's not just a repeat of the same value (see discussion here).

Current Version:

v3.2.0

[bbbales2]

This is a duplicate of: #1861

[bbbales2]

Whoops, not quite a duplicate. This is for cdfs.