global: convert trivial usages of `test <expr> -a/-o <expr>`

global: convert trivial usages of `test <expr> -a/-o <expr>`

Our coding guidelines say to not use `test` with `-a` and `-o` because
it can easily lead to bugs. Convert trivial cases where we still use
these to instead instead concatenate multiple invocations of `test` via
`&&` and `||`, respectively.

While not all of the converted instances can cause ambiguity, it is
worth getting rid of all of them regardless:

    - It becomes easier to reason about the code as we do not have to
      argue why one use of `-a`/`-o` is okay while another one isn't.

    - We don't encourage people to use these expressions.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>