Allow Process::WaitForProcessToStop to return immediately if process is already in the stopped state
- By default, the above function will wait for at least one event
- Set wait_always=false to make the function return immediately if the process is already stopped



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@192301 91177308-0d34-0410-b5e6-96231b3b80d8