[Sema debugger support] Require non-void types to be complete in unknown-anytype casts.

When performing a cast from an __unknown_anytype function call to a
non-void type, we need to make sure that type is complete. Fixes
rdar://problem/23959960.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@259681 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed