systemc: Make a test stop including an internal path for sc_vector.

systemc: Make a test stop including an internal path for sc_vector.

The sc_vector class is available through systemc.h already, so there's
no reason to include an internal path which is only there on Accellera
by coincidence of the implementation.

Change-Id: I41cab4711c0837cd9b20c21871b79be5165bf498
Reviewed-on: https://gem5-review.googlesource.com/11176
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>