Fix ShouldCreateVimBufferForHost test

Not sure how this was passing on AppVeyor.  The test was mixing the
built-in Vim / VimHost with the test local Vim / VimHost.  Changed it to
be consistent
Fix Issue 1507

The caret should be allowed into the line break in any visual / select
mode.  Whether or not the selection is exclusive doesn't appear to be
important.  I'm unsure why that particular check was originally added
but experimentation shows that it is incorrect.

closes #1507