with DR in parent and child, add consistency for code changed via IPC

Code modification via IPC is a longstanding open issue (cases 68/204553 and 8321/212756 in our old tracker in case there are references in the code). Today we just log some of the actions (e.g., "WARNING: ProtectVirtualMemory called on process xxx" or the IPC_ALERT macros). We're talking about remote NtProtectVirtualMemory, NtWriteVirtualMemory, etc. on Windows: we're not trying to handle code changed via the kernel's debugger interface.

For DR in the parent it would be possible to notify the child DR about the code change. Probably we'd use a nudge, and we'd have the parent check the child drmarker first to avoid nudging native processes.