sim: sh: simplify testsuite a bit

Switch from the centralized list in the exp file to each test declaring
its own requirements which they're already (mostly) doing.  This will
increase coverage slightly by running more tests in more configurations
since the hardcoded exp list was a little out of date.

We have to mark the psh* tests as shdsp only (to match what the exp
file was doing), mark the fsca & fsrra tests as failing (since they
weren't even being run by the exp file), and to fix the expected
output & status of the fail test.