Fixes for GDB remote packet disassembler:
Fixes for GDB remote packet disassembler:

- Add latency timings to GDB packet log summary if timestamps are on log
- Add the ability to plot the latencies for each packet type with --plot
- Don't crash the script when target xml register info is in wierd format



git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@343243 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb