sim: cris: replace custom "dest" test field with new --argv0

sim: cris: replace custom "dest" test field with new --argv0

The #dest field used in the cris testsuite is a bit of hack to set the
argv[0] for the tests to read out later on.  Now that the sim has an
option to set argv[0] explicitly, we don't need this custom field, so
let's drop it to harmonize the testsuites a little.