Cannot read TEB during leak scan in untrusted integrity process

_From [rnk@google.com](https://code.google.com/u/rnk@google.com/) on January 17, 2013 12:00:59_

The fix for issue #547 no longer works since the switch to drmgr. drmgr frees its TLS during thread exit, so we can't cache values in TLS.

I have a standalone test case of an app that lowers its integrity. We should add it to the test suite.

See also issue #1101 for issues with opening files from an untrusted process.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=1120_