[analyzer] Treat stdin as a source of taint.

Some of the test cases do not currently work because the analyzer core
does not seem to call checkers for pre/post DeclRefExpr visits.
(Opened radar://10573500. To be fixed later on.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146536 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed