Handling dynamic generated code in hybrid execution

_From [zhao...@google.com](https://code.google.com/u/106321947286816917100/) on January 13, 2014 10:17:30_

Current hybrid execution does not handle dynamically generated code well.
If a native module generates some code in a heap and executing the generated code, e.g., v8, the memory holding the generated code will be marked as no-writable for cache consistency. Later if the native module updates the generated code, e.g., add new code into the same page, it will cause a page fault, which is not handled and crash the process.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=1348_