track memory written via syscall non-pointer parameter

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on December 10, 2010 17:57:46_

PR 408533

Some system calls write to user memory based on a handle instead of direct buffer
pointer passed to syscall.
Examples includ a mmapped file (that's PR 408531) or GDI structs like RGNDATA => HRGN
(create via ExtCreateRegion(), then can pass HRGN to various routines and the data is touched)
We would have to record the address at handle creation time and match it up later.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=116_