Use getpgid() with waitpid() in case the process pgid is not equal to its pid, as is the case with a forked subprocess. Also a couple of fixes for unit test failures from Todd Fiala.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@205405 91177308-0d34-0410-b5e6-96231b3b80d8