tests: don't run test-gpg if not in a working directory test-gpg has to be run in a mercurial working directory as it uses that to verify that it hasn't modified the trustdb.gpg file. Skip the test if it is running in an exploded tarball.

tests: avoid zombie lockup with test-hup The 'while kill -0' recipe can cause a livelock if the process we're waiting to die is a normal child process. If it becomes a zombie that the shell doesn't reap (shell bug?), it will continue to be able to accept signals. So instead, we just wait(1).