set library path as a normal polyglot option, so it is checked after experimental options

Author: timfel

mx.graalpython/mx_graalpython.py

@@ -123,9 +123,11 @@ def do_run_python(args, extra_vm_args=None, env=None, jdk=None, **kwargs):
         dists.append('SULONG')
         if mx.suite("sulong-managed", fatalIfMissing=False):
             dists.append('SULONG_MANAGED')
-            vm_args.append(mx_subst.path_substitutions.substitute('-Dpolyglot.llvm.libraryPath=<path:SULONG_MANAGED_LIBS>'))
+            graalpython_args.insert(0, mx_subst.path_substitutions.substitute('--llvm.libraryPath=<path:SULONG_MANAGED_LIBS>'))
         else:
-            vm_args.append(mx_subst.path_substitutions.substitute('-Dpolyglot.llvm.libraryPath=<path:SULONG_LIBS>'))
+            graalpython_args.insert(0, mx_subst.path_substitutions.substitute('--llvm.libraryPath=<path:SULONG_LIBS>'))
+
+    graalpython_args.insert(0, '--experimental-options=true')
 
     # Try eagerly to include tools on Tim's computer
     if not mx.suite("/tools", fatalIfMissing=False):