This migrates explorer tests to file_test, using the new --autoupdate
functionality. Per discussion, the trace tests that were using "not"
output are mostly migrated to checking full output. The main exception
is tests that were including trace output from the prelude: the prelude
output is pretty long (multiple MB already) and I think it wasn't the
intent to include, only trace output from the small program.
This is the remaining use of lit support, so the supporting libraries
are also removed here.
I've migrated the toolchain autoupdate scripts here, I just need a
little more time to do the explorer side (which I need to check
performance, that may require multithreading as we do in the current
script). However, this felt substantial enough to share and it means I
can handle autoupdate in more of the toolchain, including preparatory
work for autoupdate on multi-file tests.
Once explorer is done I'll remove the old script.
Jon Ross-Perkins