Ensure jt graph is run at the repo root

eregon · eregon · commit fb2502175134 · 2022-08-29T15:55:02.000+02:00
diff --git a/tool/jt.rb b/tool/jt.rb
@@ -2069,6 +2069,7 @@ def profile(*args)
   end
 
   def graph(*args)
+    in_truffleruby_repo_root!
     truffleruby_compiler!
 
     test_file = nil
