i#1597 IAT hook conflicts: avoid using IAT for injection
i#1597 IAT hook conflicts: avoid using IAT for injection

To avoid IAT hooks injected into the frontend from messing up thread
injection, we switch from using kernel32!GetProcAddress to DR's own
routines.  We're already linking in the required files into
drinjectlib.

Fixes #1597

Review-URL: https://codereview.appspot.com/195570043

bl4ckic3/dynamorio,code4bones/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,code4bones/dynamorio,daksunt/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,AmesianX/dynamorio