Protect against bad values in `current-module-declare-name'.

Closes PR 12125

collects/racket/sandbox.rkt

@@ -897,6 +897,9 @@
        ,@(sandbox-path-permissions))]
     ;; general info
     [current-command-line-arguments '#()]
+    ;; prevent a potential value here from messing up creating the sandboxed
+    ;; module
+    [current-module-declare-name #f]
     ;; restrict the sandbox context from this point
     [current-security-guard
      (let ([g (sandbox-security-guard)]) (if (security-guard? g) g (g)))]

collects/tests/racket/sandbox.rktl

@@ -500,4 +500,11 @@
 
    ))
 
+(parameterize ([current-module-declare-name (make-resolved-module-path 'junk)])
+  (define (avoid-module-declare-name)
+    (with-handlers ([exn? (lambda (_) #f)])
+      (kill-evaluator (make-evaluator 'racket/base))
+      #t))
+  (test #t avoid-module-declare-name))
+
 (report-errs)