Add -dynamic for integration and stress tests with Cray compiler wrappers

Cray systems come with compiler wrappers to simplify building parallel
applications. CC is the C++ wrapper, and cc is the C wrapper.

The wrappers call the base {Cray, Intel, PGI, or GNU} compiler with vendor
specific flags. The "Programming Environment" (prgenv) that's currently loaded
determines the base compiler. e.g. compiling with gnu looks something like:

    module load PrgEnv-gnu
    cc hello.c

On most systems the wrappers defaults to `-static` mode, which causes them to
only look for static libraries, and not for any dynamic ones (even if the
dynamic version was explicitly listed.)

The integration and stress tests expect to be using the .so, so we have to run
the with -dynamic so that wrapper will find/use the .so.