Make TR class tests run successfully on their own

Closes PR 14409

original commit: da3bc2f266c31ef912dc4b1e0a6ba77610d6ed9b

pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/class-tests.rkt

@@ -4,11 +4,17 @@
 
 (require (submod "typecheck-tests.rkt" test-helpers)
          (except-in "test-utils.rkt" private)
-         (for-syntax racket/base))
+         (for-syntax racket/base
+                     typed-racket/tc-setup
+                     typed-racket/utils/tc-utils))
 
 (provide tests)
 (gen-test-main)
 
+(begin-for-syntax
+  ;; for checking the printing of type aliases
+  (current-type-names (init-current-type-names)))
+
 ;; see typecheck-tests.rkt for rationale on imports
 (require rackunit
          (except-in racket/class class)