Move almost all the code of this script into functions. There is no
intended behavior change. The goal of this commit is to make
subsequent improvements easier to follow.
A very large number of lines have been reintended. To see what's going
on, ignore whitespace differences (e.g. diff -w).
I followed the following rules:
* Minimize the amount of code that gets moved.
* Don't change anything to what gets executed or displayed.
* Almost all the code must end up in a function.
This commit is in preparation for breaking up the sequence of tests
into individual components that can run independently.