[mlir][Linalg] Allow decompose to handle ops when value of `outs` operand is used in payload.

Current implementation of decomposition of Linalg operations wouldnt
work if the `outs` operand values were used within the body of the
operation. Relax this restriction. This potentially sets the stage for
decomposing ops with reduction iterator types (but is not done here
since it requires more study).

Differential Revision: https://reviews.llvm.org/D130527