This doesn't claim to support ShTest tests yet, but I've added in a hacked-together wrapper script remoteRun.py as one possible solution. I'm still not certain how to orchestrate executable copy-in for those cases.
Here I've also punted on what to do about test data files. The affected tests are:
libc++ :: std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp libc++ :: std/input.output/file.streams/fstreams/filebuf.virtuals/underflow.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.assign/member_swap.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.assign/move_assign.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.assign/nonmember_swap.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.cons/move.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.cons/pointer.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.cons/string.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.members/close.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.members/open_pointer.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.members/open_string.pass.cpp libc++ :: std/input.output/file.streams/fstreams/ifstream.members/rdbuf.pass.cpp libc++ :: std/localization/locales/locale.convenience/conversions/conversions.buffer/pbackfail.pass.cpp libc++ :: std/localization/locales/locale.convenience/conversions/conversions.buffer/underflow.pass.cpp
I tested this on my mac with an SSHExecutor that connects to localhost, and copies executables into /tmp to get a feel for the overhead. That run took ~414s, whereas a normal one takes about half that at ~204s.
This isn't quite ready for commit, but it's a lot closer... There's still a few things I'd like to pick your brains on, @danalbert and @EricWF.