tests: remove hand-written parallelism in testcompat-*openssl tests
In testcompat-main-openssl, we have the following hand-written code to run sub-testsuites in parallel:
WAITPID=""
for mod in "" ":%COMPAT" ":%NO_ETM" ":%NO_TICKETS" ":%DISABLE_SAFE_RENEGOTIATION" ":%SAFE_RENEGOTIATION"; do
run_server_suite $mod &
WAITPID="$WAITPID $!"
done
We should rely on automake's parallel-tests harness by having individual test scripts.