Add a new system runtime plugin type - just the top level
class, not any actual plugin implementation yet.
<rdar://problem/15314068> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194044 91177308-0d34-0410-b5e6-96231b3b80d8
Add a GetThreadOriginExtendedBacktraceTypes method to the
SystemRuntime class.
<rdar://problem/15314369> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194045 91177308-0d34-0410-b5e6-96231b3b80d8