Correct test to target 'unknown'

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196060 91177308-0d34-0410-b5e6-96231b3b80d8
Fix inconsistent diag name

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196061 91177308-0d34-0410-b5e6-96231b3b80d8
Correct a user-visible static analyzer message typo

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196062 91177308-0d34-0410-b5e6-96231b3b80d8