Clear memory after loading external weights (#435)

It fixes OOM if terminating the program by keyboard.

---------

Co-authored-by: Ean Garvey <[email protected]>

Author: jinchen62

models/turbine_models/model_runner.py

@@ -60,7 +60,8 @@ def __init__(self, device, vmfb_path, external_weight_path=None):
                     self.config.vm_instance, index.create_provider(scope="model")
                 )
                 vm_modules.insert(i, param_module)
-
+            del index
+            del param_module
         self.ctx = ireert.SystemContext(
             vm_modules=vm_modules,
             config=self.config,