[analyzer] UnixAPI: Check when open(2) is called with more than three arguments.

Patch by Daniel Fahlgren.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216078 91177308-0d34-0410-b5e6-96231b3b80d8
[analyzer] UnixAPI: Check that the third argument to open(2) (if present) is an integer.

Patch by Daniel Fahlgren.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216079 91177308-0d34-0410-b5e6-96231b3b80d8