`affine::replaceForOpWithNewYields` and `replaceLoopWithNewYields` (for
"scf.for") are now interface methods and additional loop-carried
variables can now be added to "scf.for"/"affine.for" uniformly. (No more
`TypeSwitch` needed.)
Note: `scf.while` and other loops with loop-carried variables can
implement `replaceWithAdditionalYields`, but to keep this commit small,
that is not done in this commit.
63086d6aa0