btest dislikes Emacs temporary files

[timwoj]

btest has problems with some of the temporary files that Emacs creates. These are both with the default configuration for how emacs stores temporary files (meaning they're stored in the same directory as the original file).

• When creating a new file but before you've committed it to git, a filename.zeek~ file gets created by Emacs. If you try to run btest on the filename.zeek file, btest picks up the tilde-file instead.
• When editing an existing file but before you've saved it, a .#filename.zeek file gets created. If you try to run btest on the filename.zeek file, btest picks up the dothash-file instead.

I've run into both of these enough times that you'd think I'd notice when it happens, but this ticket is evidence that I don't pay enough attention.