commands: Test finding sorted builtins and scripts
commands: Test finding sorted builtins and scripts

Given the mergesort algorithm employed in the test and the array pattern
substitution trick from a couple commits back, once this test suite is done,
I'll replace the insertion sort, parallel array implementation of
`_@go.find_commands` with one that uses mergesort and only the
`__go_command_scripts` array. Should be a little faster, a little less code.

mbland/go-script-bash