Summary:
Fix https://github.com/facebook/flipper/issues/808
Kills any orphaned Instruments processes belonging to the user.
In some cases, we've seen interactions between Instruments and the iOS
simulator that cause hung instruments and DTServiceHub processes. If
enough instances pile up, the host machine eventually becomes
unresponsive. Until the underlying issue is resolved, manually kill any
orphaned instances (where the parent process has died and PPID is 1)
before launching another instruments run.
Taking the same approach as done by flutter here.
Reviewed By: passy
Differential Revision: D20030005
Pulled By: jknoxville
fbshipit-source-id: aa80be78c80f7797e88bf29b15f90d4aad0c66e4
