[mlir][linalg][bufferize] Reimplementation of scf.if bufferization

Instead of modifying the existing scf.if op, create a new op with memref OpOperands/OpResults and delete the old op.

New allocations / other memrefs can now be yielded from the op. This functionality is deactivated by default and guarded against by AssertDestinationPassingStyle.

Differential Revision: https://reviews.llvm.org/D115491