Fix exception handling in fibers-map-with-progress

tests/parallelism.scm

@@ -61,6 +61,24 @@
     identity
     '(()))))
 
+(run-fibers-for-tests
+ (lambda ()
+   (with-exception-handler
+       (lambda (exn)
+         (unless (and (exception-with-message? exn)
+                      (string=? (exception-message exn)
+                                "foo"))
+           (raise-exception exn)))
+     (lambda ()
+       (fibers-map-with-progress
+        (lambda _
+          (raise-exception
+           (make-exception-with-message "foo")))
+        '((1)))
+
+       (error 'should-not-reach-here))
+     #:unwind? #t)))
+
 (run-fibers-for-tests
  (lambda ()
    (with-exception-handler