updated test_language and add walker update code

jaclang/tests/fixtures/walker_update.jac

@@ -0,0 +1,19 @@
+import:jac from bar { bar_walk }
+import:py from jaclang.runtimelib.machine { JacMachine }
+import:py os;
+
+can update_bar_walker {
+    "Updating bar.jac with new behavior." |> print;
+    (bar_walk_new, ) = JacMachine.get().update_walker(
+        "bar",
+        items={'bar_walk': None}
+    );
+    "Running bar_walk after update..." |> print;
+    root spawn bar_walk_new();
+    print(f"bar_walk: {bar_walk_new.__dict__}");
+}
+
+
+with entry {
+    update_bar_walker();
+}

jaclang/tests/test_language.py

@@ -956,6 +956,7 @@ def test_walker_dynamic_update(self) -> None:
         """Test dynamic update of a walker during runtime."""
         session = self.fixture_abs_path("bar_walk.session")
         bar_file_path = self.fixture_abs_path("bar.jac")
+        update_file_path = self.fixture_abs_path("walker_update.jac")
         captured_output = io.StringIO()
         sys.stdout = captured_output
         cli.enter(
@@ -996,11 +997,8 @@ def test_walker_dynamic_update(self) -> None:
         sys.stdout = captured_output
 
         try:
-            cli.enter(
-                filename=bar_file_path,
-                session=session,
-                entrypoint="bar_walk",
-                args=[],
+            cli.run(
+                filename=update_file_path,
             )
             sys.stdout = sys.__stdout__
             stdout_value = captured_output.getvalue()