UnitTestFrameworkPkg: Library classes private to public

UnitTestFrameworkPkg: Library classes private to public

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4178

* Change GoogleTestLib class from private to public.
* Change UnitTestPersistenceLib class from private to public.

Cc: Michael Kubacki <mikuback@linux.microsoft.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>