We were leaking a stack frame in StackFrameList in Thread.cpp which could

cause extra shared pointer references to one or more modules to be leaked.
This would cause many object files to stay around the life of LLDB, so after
a recompile and rexecution, we would keep adding more and more memory. After
fixing the leak, we found many cases where leaked stack frames were still
being used and causing crashes in the test suite. These are now all resolved.

llvm-svn: 137516