Revision-related tweaks for next-solver tests
1. Add `ignore-compare-mode-next-solver` to any test that already has explicit `current next` revisions, since the test failures when testing with `--compare-mode=next-solver` will be false positives.
2. Explicitly add revisions to a handful of tests where we expect behavior to diverge.
r? lcnr
a11e6c38b5