libc: Add pthread and stdio benchmark test programs.

This patch adds two test programs to system/extras/test/bionic/libc

The first one can be used to benchmark simple stdio operation
(for now fread() / fwrite()).

The second one can be used to benchmark misc. pthread operations.
It can also easily be built with other toolchains for comparison
with other C library / pthread implementations.

Change-Id: I3e611244f3ff95e7485d8b8d6f91e5b8bab2de4b
3 files changed