Move all libcutils tests into the gtests.

This also fixes the bug where we were always testing against the fake
strlcpy we provide for glibc/Windows rather than the Android one.

This also removes some unnecessary library dependencies.

This also builds all the cutils tests for the host (static and dynamic).

Change-Id: Icd129d5b025c0ca801be5acf31a54ecd88608df9