[MLIR][scf.parallel] Don't allow a tile size of 0 (#68762)

Fix a crash reported in #64331. The crash is described in the following
comment:

> It looks like the bug is being caused by the command line argument
--scf-parallel-loop-tiling=parallel-loop-tile-sizes=0. More
specifically, --scf-parallel-loop-tiling=parallel-loop-tile-sizes sets
the tileSize variable to 0 on [this
line](https://github.com/llvm/llvm-project/blob/7cc1bfaf371c4a816cf4e62fe31d8515bf8f6fbd/mlir/lib/Dialect/SCF/Transforms/ParallelLoopTiling.cpp#L67).
tileSize is then used on [this
line](https://github.com/llvm/llvm-project/blob/7cc1bfaf371c4a816cf4e62fe31d8515bf8f6fbd/mlir/lib/Dialect/SCF/Transforms/ParallelLoopTiling.cpp#L117)
causing a divide by zero exception.

This PR will:

1. Call `signalPassFail()` when 0 is passed as a tile size.
2. Avoid the divide by zero that causes the crash. 

Note: This is my first PR for MLIR, so please liberally critique it.