By constructing an arg vector manually, we no longer need to quote arguments
Mandate that args must be passed when building a command
Now you need to provide an args array when building a command.
There are a handful of places where we need to deal with a string,
such as with user-defined custom commands, and for those we now require
that at the callsite they use str.ToArgv to do that. I don't want
to provide a method out of the box for it because I want to discourage its
use.
For some reason we were invoking a command through a shell when amending a
commit, and I don't believe we needed to do that as there was nothing user-
supplied about the command. So I've switched to using a regular command out-
side the shell there
If you ran this test enough times it would eventually fail; this happened
whenever the resulting squashed commit had a sha that happened to start with
"02". We test that "commit 02" does not appear in the diff window, but in that
case it did, at the very top of the window.
A better fix might be to change the commit message that we use in CreateNCommits
to something other than "commit XY", but that would require touching tons of
tests, so this is the easier fix.