effects: Refine effects for getfield of unknown field
When all fields are known initialized syntactically, we do not
need to test whether accessing the fields will give an UndefRef.
We only need to check for the fields that are not syntactically
known to be initialized.
As a result, this commit improves `:consistent`-cy of `getfield` call,
which is better in general but leads to inference/inlining accuracy
regression in some edge cases because now irinterp is enabled on more
frames. There are two regressions, but we are fine with them so we
modify the test cases:
- inlining regression: irinterp ends up some extra junk basic blocks,
that LLVM can optimize away down the road.
- inference regressions: these regressions are all related to the
`MustAlias` lattice extension, which was added for JET's use case
especially and not enabled in base yet. Since JET doesn't enable
irinterp, this commit marks the regressed cases as broken.
