testsuite: rename exceptions used in uncaught_exception_handler test …

…case in lib-threads for readability

testsuite/tests/lib-threads/uncaught_exception_handler.ml

@@ -14,16 +14,19 @@ include systhreads
 
 let () = Printexc.record_backtrace true
 
+exception UncaughtHandlerExn
+exception CallbackExn
+
 let handler exn =
   let id = Thread.self () |> Thread.id in
   let msg = Printexc.to_string exn in
   Printf.eprintf "[thread %d] caught %s\n" id msg;
   Printexc.print_backtrace stderr;
   flush stderr;
-  raise exn
+  raise UncaughtHandlerExn
 
 let fn () = Printexc.raise_with_backtrace
-              Not_found
+              CallbackExn
               (Printexc.get_raw_backtrace ())
 
 let _ =

testsuite/tests/lib-threads/uncaught_exception_handler.reference

@@ -1,12 +1,12 @@
-Thread 1 killed on uncaught exception Not_found
-Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 25, characters 12-111
-Called from Thread.create.(fun) in file "thread.ml", line 47, characters 8-14
-[thread 2] caught Not_found
-Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 25, characters 12-111
-Called from Thread.create.(fun) in file "thread.ml", line 47, characters 8-14
-Fatal error in thread 2 : Not_found
-Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 25, characters 12-111
-Called from Thread.create.(fun) in file "thread.ml", line 47, characters 8-14
-Fatal error in uncaught exception handler : Not_found
-Raised at Uncaught_exception_handler.handler in file "uncaught_exception_handler.ml", line 23, characters 2-11
-Called from Thread.create.(fun) in file "thread.ml", line 53, characters 10-41
+Thread 1 killed on uncaught exception Uncaught_exception_handler.CallbackExn
+Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 28, characters 12-113
+Called from Thread.create.(fun) in file "thread.ml", line 51, characters 8-14
+[thread 2] caught Uncaught_exception_handler.CallbackExn
+Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 28, characters 12-113
+Called from Thread.create.(fun) in file "thread.ml", line 51, characters 8-14
+Thread 2 killed on uncaught exception Uncaught_exception_handler.CallbackExn
+Raised at Uncaught_exception_handler.fn in file "uncaught_exception_handler.ml", line 28, characters 12-113
+Called from Thread.create.(fun) in file "thread.ml", line 51, characters 8-14
+Thread 2 uncaught exception handler raised Uncaught_exception_handler.UncaughtHandlerExn
+Raised at Uncaught_exception_handler.handler in file "uncaught_exception_handler.ml", line 26, characters 2-26
+Called from Thread.create.(fun) in file "thread.ml", line 57, characters 10-41