[lit.py] setUp and tearDown in lit?

Hello everyone.

I’m working on supporting remote testing for libc++ (which is useful if you’re cross-compiling libc++).

For running libc++ tests on the target machine I compile libc++.so on my host machine and copy it via scp to the target before running each test. As you can imagine, this is pretty slow.

I’d like to be able to copy libc++.so to the target once before running the first test in a batch, and then delete it from the target after running the last test in that batch.

Are there any customization points for this in lit? If no, do you think it’s a good idea to add them, for example, as optional methods `setUp` and `tearDown` on a test_format object, which could be implemented by those format classes that need this functionality?