Convert perl util scripts to python

[jayeshkrishna]

There are several perl utility scripts in PIO. Since CIME has moved to python it would make sense to port all of the existing scripts to python (eventually).

The following scripts are currently in perl.

./scripts/prune_decomps.pl
./tests/general/util/pio_tf_f90gen.pl
./tests/performance/gensimple.pl
./examples/basic/testpio_build.pl
./examples/basic/testpio_run.pl
./examples/basic/testpio_bench.pl