[mlir][linalg][bufferize] Remove buffer equivalence from bufferize

Remove all function calls related to buffer equivalence from bufferize implementations.

Add a new PostAnalysisStep for scf.for that ensures that yielded values are equivalent to the corresponding BBArgs. (This was previously checked in `bufferize`.) This will be relaxed in a subsequent commit.

Note: This commit changes two test cases. These were broken by design
and should not have passed. With the new scf.for PostAnalysisStep, this
bug was fixed.

Differential Revision: https://reviews.llvm.org/D114927