Without this patch, we'd always try to codesign the first argument in
the command line, which in some cases is not something we can codesign
(e.g. `bash` for some .sh.cpp tests).
Note that this "hack" is the same thing we do in `ssh.py` - we might need
to admit that it's not a hack after all in the future, but I'm not ready
for that yet.
Differential Revision: https://reviews.llvm.org/D99726
232d3a3e47