fix using enableLVI

Author: timfel

mx.graalpython/mx_graalpython.py

@@ -137,7 +137,7 @@ def _is_user(user, home=None):
             SUITE.import_suite("tools", version=None, urlinfos=None, in_subdir=True)
             dists.append('CHROMEINSPECTOR')
             if SUITE_SULONG:
-                vm_args.append("-Dpolyglot.llvm.enableLVI=true")
+                graalpython_args.insert(1, "--llvm.enableLVI=true")
 
     vm_args += mx.get_runtime_jvm_args(dists, jdk=jdk)