Tests that depend on supported features such as menu completions, list
view, inline predictions, continuation prompt, and colors are skipped.
The "helper" module for running tests from the command-line and in
AppVeyor is minimally updated to not skip the new fixture.
A `BlankRestOfBuffer()` function implements the semantics of the `0J`
control sequence in the mock console.
This character was always meant to be an ellipsis. I'm unsure exactly
why Visual Studio interprets it so, but VS Code and GitHub do not. This
commit replaces it with the actual Unicode character which ensures the
tests continue to pass when these files are edited and saved in VS Code.
Andy Jordan