gdbremote testing: added regex support to match packets and propagate/test against previously stored matches.

Added a test validating that $qC after an inferior launch via $A
returns a thread id that an immediately followig $? reports for the
active thread. This is currently skipped on debugserver (the thread
ids don't match) and isn't yet implemented in TOT for llgs.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@208061 91177308-0d34-0410-b5e6-96231b3b80d8