* Don't include <sys/resource.h> on Fuchsia.

It doesn't support POSIX resource measurement and timing APIs.

Change-Id: Ifab4bac4296575f042c699db1ce5a4f7c2d82893

* Add BENCHMARK_OS_FUCHSIA for Fuchsia

Change-Id: Ic536f9625e413270285fbfd08471dcb6753ddad1