I don't know why this works for me locally but not on travis, although
it is harder for me to be sure this machine is completely clean! So the
easiest way to find out if this fixes the problem is probably just to
try it...
We also need to separate building the runtests binary from running the
tests, because runtests refers to the boostrap libraries, and the tests
refer to the newly built libraries.
This worked locally, using inconsistent TTC versions for the bootstrap
version and new version, but let's see what it does on a clean machine
I think the tests are using the libraries from the bootstrap Idris 2, not
the just built Idris 2, so if the ttc formats aren't idential the tests
won't work. Let's see if that theory is correct...
It's better if the tests aren't interactive, since they're intended for
running on CI as well as to give an idea of whether building was
successful, rather than to give an idea of what has gone wrong.
Need to pass the LD_LIBRARY_PATH all the way through or racket doesn't
know where to look. I really don't know why it doesn't work to just set
it at the top level in the script, but it didn't (on my Mac, at least).
