misc/ios: don't wait for response to lldb run in the exec wrapper
CL 106096 changed the iOS exec wrapper to directly run the binary
without waiting for a SIGINT signal, but did so in a way that
expects a "(lldb)" response from lldb in 2 seconds. Lldb might
not out output anything until the program finishes, so change the
exec wrapper to just fire and forget the the run command and go
straight to waiting for exit, successfully or otherwise.