This patch adds sending messages larger than just hal_hdr, and fixes
response verification which worked only for empty messages but was
failing when sending something more than just header.
This patch adds tests for calling proper opcode handler. Two handlers
are registered, but one always results in failure. No failure means that
proper opcode <-> handler maching is done by the ipc mechanism.
This handler responses for opcode == 1, thus should use proper naming to
avoid confision when more functions sending different responses will be
added.
This fix makes sure that when signalled termination is expected,
it actually happens. If IPC termination is expected no response will be
sent, so cmd_watch will never be executed. But if it is executed when
expecting termination, its a failure.
