[mlir][transform][linalg][python] Fix test for TileToForallOp mixin.

The test was introduced recently by https://reviews.llvm.org/D155090,
but https://reviews.llvm.org/D155567, which I worked on concurrently
affected the output of that test and the two patches were never tested
together.

Differential Revision: https://reviews.llvm.org/D155709