sim: cris: drop custom "dynamic" test field

sim: cris: drop custom "dynamic" test field

This tag is used to force tests to be built dynamically (i.e. without
-static linking).  This is because cris-sim.exp in dejagnu turns on
static linking in ldflags.

The default configs and runtest flags shouldn't load these boards.
If these settings are still needed, we should figure out a different
way of suppressing the stock settings wholesale.  We want these to
all pass out of the box with little to no configuration so that they
can run in a multitarget build.

With dropping "dynamic", it'll be easier to merge the custom cris
test logic with the common sim test logic.