bench: cpython vm defaults to no warmup curves

- update overlay

Author: cosminbasca

ci.jsonnet

@@ -3,7 +3,7 @@ local const = import 'ci_common/constants.libsonnet';
 local builder = import 'ci_common/builder.libsonnet';
 
 {
-    overlay: "e53f9686acc713d79098a608a00101733e26ba39",
+    overlay: "123dda879b0003af4b8d529e71fceb15bb26e94e",
 
     // ======================================================================================================
     //

mx.graalpython/mx_graalpython_benchmark.py

@@ -158,7 +158,7 @@ def run(self, cwd, args):
 class CPythonVm(AbstractPythonIterationsControlVm):
     PYTHON_INTERPRETER = "python3"
 
-    def __init__(self, config_name, options=None, virtualenv=None, iterations=None):
+    def __init__(self, config_name, options=None, virtualenv=None, iterations=0):
         super(CPythonVm, self).__init__(config_name, options=options, iterations=iterations)
         self._virtualenv = virtualenv