message: Remove more dead code from NativeProcessLinux
  This should have been removed in r334333.
diff: @@ -184,20 +184,6 @@ private:
  Status SetupSoftwareSingleStepping(NativeThreadLinux &thread);
  -#if 0
  - static ::ProcessMessage::CrashReason
  - GetCrashReasonForSIGSEGV(const siginfo_t *info);
  -
  - static ::ProcessMessage::CrashReason
  - GetCrashReasonForSIGILL(const siginfo_t *info);
  -
  - static ::ProcessMessage::CrashReason
  - GetCrashReasonForSIGFPE(const siginfo_t *info);
  -
  - static ::ProcessMessage::CrashReason
  - GetCrashReasonForSIGBUS(const siginfo_t *info);
  -#endif
  -
  bool HasThreadNoLock(lldb::tid_t thread_id);
  bool StopTrackingThread(lldb::tid_t thread_id);
  