injection fails on win7 with ymm state in context flags

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on May 04, 2011 16:02:53_

r754 ( issue #433 ) seems to have broken win7 on my laptop: though I tested win7 at some point before I committed so not clear what the difference is.

in any case the problem is including CONTEXT_XSTATE when asking for a thread's context. inject_into_thread doesn't have underlying processor info so it blindly uses all the flags.

xref issue #437 for now just disabling CONTEXT_XSTATE for injection. will leave issue open for better fix.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=444_