Silence static analyzer getAs<RecordType> null dereference warnings. NFCI.

The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<RecordType> directly and if not assert will fire for us.

llvm-svn: 373584
diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index fd843e4..0f3a272 100644
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -154,7 +154,7 @@
     ReturnValueOnError = false;
   }
   if (!(PointeeT->isRecordType() &&
-        PointeeT->getAs<RecordType>()->isBeingDefined()) &&
+        PointeeT->castAs<RecordType>()->isBeingDefined()) &&
       RequireCompleteType(Range.getBegin(), PointeeT, DiagID, Kind, Range))
     return ReturnValueOnError;