Fix broken check in getUnionType (check was always true)

Author: ahejlsberg

src/compiler/checker.ts

@@ -9359,7 +9359,7 @@ namespace ts {
                 }
                 switch (unionReduction) {
                     case UnionReduction.Literal:
-                        if (includes & TypeFlags.StringOrNumberLiteralOrUnique | TypeFlags.BooleanLiteral) {
+                        if (includes & (TypeFlags.Literal | TypeFlags.UniqueESSymbol)) {
                             removeRedundantLiteralTypes(typeSet, includes);
                         }
                         break;