Avoid correcting unknown identifiers to types where types aren't allowed.

Avoid correcting unknown identifiers to types where types aren't allowed.

Pass a typo correction callback object from ParseCastExpr to
Sema::ActOnIdExpression to be a bit more selective about what kinds of
corrections will be allowed for unknown identifiers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148973 91177308-0d34-0410-b5e6-96231b3b80d8