Send default register number instead of GDB register number in StopReplyPacket.

Summary:
Using GDB register numbers confuses ProcessGDBRemote since the rest of
LLGS (qRegisterInfo, p, P) uses the default register numbers instead.

Test Plan: dosep.py --options --arch x86 ...

Reviewers: ovyalov, vharron, sivachandra

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D7635

llvm-svn: 229505