Integrate tools/regression/lib/libc (minus regex) into ATF/kyua

The .t files were moved to .sh if needed; nuked otherwise.
For all cases where the wrapper .sh files needed to be preserved,
the *.c file was renamed to *_helper.c

gen/test_driver.sh is a simple script that was written to wrap
around testcases that were not TAP-friendly to make the output
TAP friendly.

The tools/regression/lib/libc/regex testcases do not compile after
the xlocale changes made in the past couple years, so it will remain
deorbited for now.

Sponsored-by: EMC / Isilon Storage Division
Prune orphaned prove wrapper script

Sponsored-by: EMC / Isilon Storage Division