Unbreak TR's top-level

A recent change I made broke optimizations at the top-level

pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/core.rkt

@@ -73,9 +73,12 @@
      (tc-toplevel/full stx #'form
        (λ (body2 type)
          (with-syntax*
-          ([(transformed-body ...)
-            (change-contract-fixups (flatten-all-begins body2))]
-           [(optimized-body ...) (maybe-optimize #'(transformed-body ...))])
+          ([(optimized-body ...) (maybe-optimize #`(#,body2))]
+           ;; Transform after optimization for top-level because the flattening will
+           ;; change syntax object identity (via syntax-track-origin) which doesn't work
+           ;; for looking up types in the optimizer.
+           [(transformed-body ...)
+            (change-contract-fixups (flatten-all-begins #'(begin optimized-body ...)))])
           (syntax-parse body2
             [_ (let ([ty-str (match type
                                ;; 'no-type means the form is not an expression and
@@ -126,5 +129,5 @@
                               #,(if (unbox include-extra-requires?)
                                     extra-requires
                                     #'(begin))
-                              #,(arm #'(begin optimized-body ...)))
-                     (arm #'(begin optimized-body ...))))]))))]))
+                              #,(arm #'(begin transformed-body ...)))
+                     (arm #'(begin transformed-body ...))))]))))]))

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

@@ -100,6 +100,10 @@
     (test-form #rx"^$"
       (struct foo ()))
 
+    ;; Make sure that optimized expressions work
+    (test-form #rx"Flonum"
+      (+ 1.0 2.0))
+
     ;; PR 14487
     (test-form-not-exn
       (require/typed racket/base