Recognize new name of Graal-based Python as jitted (#139)

`sys.implementation.name` was changed in recent Graal nightlies.

pyperf/_utils.py

@@ -205,7 +205,7 @@ def python_has_jit():
     implementation_name = python_implementation()
     if implementation_name == 'pypy':
         return sys.pypy_translation_info["translation.jit"]
-    elif implementation_name == 'graalpython':
+    elif implementation_name in ['graalpython', 'graalpy']:
         return True
     elif hasattr(sys, "pyston_version_info") or "pyston_lite" in sys.modules:
         return True