Add teardown hook to shutdown an inferior process

Summary: Add teardown hook to shutdown an inferior process

Reviewers: jasonmolenda, clayborg, tberghammer

Reviewed By: clayborg, tberghammer

Subscribers: lldb-commits, tberghammer, clayborg, jasonmolenda

Differential Revision: http://reviews.llvm.org/D9018

llvm-svn: 235005