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/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index f2ab27f..38c502d 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -14509,7 +14509,7 @@
     QualType BaseType = ME->getBase()->getType();
     if (ME->isArrow())
       BaseType = BaseType->getPointeeType();
-    RecordDecl *RD = BaseType->getAs<RecordType>()->getDecl();
+    RecordDecl *RD = BaseType->castAs<RecordType>()->getDecl();
     if (RD->isInvalidDecl())
       return;