llgs: removed some wait-for-stop code in inferior process launch pipeline.

The $A handler was unnecessarily waiting for the launched app to hit a stop
before returning.  Removed this code.

Renamed the llgs inferior launching code to LaunchProcessForDebugging ()
to prevent it from possibly being mistaken as code that lldb-platform uses
to launch a debugserver process.  We probably want to look at breaking out
llgs-specific and lldb-platform-specific code into separate derived classes,
with common code in a shared base class.