* Use print as a function, not as a statement
* Commonise the code for compiling and getting binary statistics into
a reusable function
* Pull out `VERBOSE` and `NUM_ITERATIONS` as top-level constants, to
make it clear where/how to change them.
* Use a docstring rather than a block comment.
* In the original version, `"Iteration {}:".format(iteration)` would
index from 0; in human-readable output, index 1 is more sensible.
A script checks if the output object file is written only once even if the compiler is invoked multiple times.
The main purpose of this check is to ensure that the compiler is deterministic (until IRGen).
