[run-jsc-stress-tests] Catch user error

https://bugs.webkit.org/show_bug.cgi?id=240905

Reviewed by Adrian Perez de Castro and Jonathan Bedard.

When the user has made a typo in the argument to --filter (selecting no
tests to execute), bring that to the user's attention instead of exiting
without an error.

* Tools/Scripts/run-jsc-stress-tests:

Canonical link: https://commits.webkit.org/250977@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294825 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Tools/Scripts/run-jsc-stress-tests

@@ -2462,6 +2462,11 @@ def prepareBundle
         handleCollection(collection)
     }
 
+    if $runlist.size == 0
+        $stderr.puts("No tests selected for execution (overzealous --filter?)")
+        exit(2)
+    end
+
     puts
 end