python fusion test does not run

[ftynse]

The python/fusion/test.py has the main function, but is never called, so running it with python -m does nothing and predictably succeeds.

[gysit]

After #55 the main function will be called. However, the test does only compile and print the IR for now. Adding verification and performance measurements is still a TODO.

[MaheshRavishankar]

If you see the TODO here (https://github.com/google/iree-llvm-sandbox/blob/fc5dcf3d511bfdaa1033475541292191aaeaa0ce/python/fusion/test.py#L52) it should work when run manually (comments use bazel but same should work with CMake). Issue when I tried this first time around is that I didnt have a driver for the lit tests from bazel. I have no idea how any of the python stuff is setup, but would be great to enable this. I know core already has this.

[ftynse]

Well it does "run" and does nothing because main is never called, bazel or not. The only check performed by FileCheck is the absence of "FAILURE" printed, which is the case when the code does nothing and prints nothing.