Create the framework and testing environment for MLIR Reduce - a tool

with the objective to reduce large test cases into smaller ones while
preserving their interesting behavior.

Implement the framework to parse the command line arguments, parse the
input MLIR test case into a module and call reduction passes on the MLIR module.

Implement the Tester class which allows the different reduction passes to test the
interesting behavior of the generated reduced variants of the test case and keep track
of the most reduced generated variant.