Initialize the non-trivial C union bits I added to RecordDeclBitfields

in r365985

These bits weren't being initialized in the RecordDecl's constructor,
which probably caused test/Modules/stress1.cpp to fail on a couple of
bots.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@365989 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/Decl.cpp

@@ -4252,6 +4252,9 @@ RecordDecl::RecordDecl(Kind DK, TagKind TK, const ASTContext &C,
   setNonTrivialToPrimitiveDefaultInitialize(false);
   setNonTrivialToPrimitiveCopy(false);
   setNonTrivialToPrimitiveDestroy(false);
+  setHasNonTrivialToPrimitiveDefaultInitializeCUnion(false);
+  setHasNonTrivialToPrimitiveDestructCUnion(false);
+  setHasNonTrivialToPrimitiveCopyCUnion(false);
   setParamDestroyedInCallee(false);
   setArgPassingRestrictions(APK_CanPassInRegs);
 }