fix SWB annotation for union

Author: MikeHolman

lib/Runtime/Library/JavascriptMap.h

@@ -37,7 +37,9 @@ namespace Js
             Field(SimpleVarDataMap*) simpleVarMap;
             Field(ComplexVarDataMap*) complexVarMap;
             MapUnion() {}
-        } u;
+        };
+
+        Field(MapUnion) u;
 
         Field(MapKind) kind = MapKind::EmptyMap;
 

lib/Runtime/Library/JavascriptSet.h

@@ -45,7 +45,9 @@ namespace Js
             Field(ComplexVarDataSet*) complexVarSet;
             Field(BVSparse<Recycler>*) intSet;
             SetUnion() {}
-        } u;
+        };
+
+        Field(SetUnion) u;
 
         Field(SetKind) kind = SetKind::EmptySet;