Small fix for i386 extended backtraces; wasn't skipping a
4-byte reserved area when reading the libBacktraceRecording API results.
Also, add a little logging about queues being created.
<rdar://problem/16127752> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@202306 91177308-0d34-0410-b5e6-96231b3b80d8