sim: testsuite: delete configure script

sim: testsuite: delete configure script

Now that we've moved all ports to dejagnu & testsuite/sim/, the only
thing the testsuite/configure script has been doing is filling in the
sim_arch field in the testsuite/Makefile.  We can simply let the top
sim/configure script do that for us now.  This simplifies & speeds up
the build a bit by killing an entire configure script.