[MergeICmps][NFC] Re-generate tests with update_test_checks.
And use a more compact name for the tested struct.
@courbet This has unearthed an intermittent issue with EXPENSIVE_CHECKS build, with entry-block-shuffled.ll and/or split-block-does-work.ll SOMETIMES failing in one run, and then passing in the next.
This smells like an uninitialized value but I haven't found anything. Please can you take a look while you are working on this code? sanitizer build-bots haven't caught anything but I don't think we have any that also have EXPENSIVE_CHECKS enabled.