These cases have been disabled for a while, and we have transitioned to
using a compact file format for incremental test cases.

I was originally planning to port all of these cases, but the vast
majority aren't testing anything interesting, so it wasn't worth the
effort. I did look through each one; anything interesting being tested
has been extracted into a new case in `test/incremental/`.

Two of the new tests are currently failing with the self-hosted ELF
linker, and thus are currently only enabled with the C backend.

Resolves: #12844