gh-156466: fix cleanup on error in codegen_setup_annotations_scope (#156473)

Python/codegen.c

diff --git a/Python/codegen.c b/Python/codegen.c
index bedf3b1..df52f2c 100644
--- a/Python/codegen.c
+++ b/Python/codegen.c
@@ -707,16 +707,8 @@ codegen_enter_scope(compiler *c, identifier name, int scope_type,
 }
 
 static int
-codegen_setup_annotations_scope(compiler *c, location loc,
-                                void *key, PyObject *name)
+codegen_emit_annotations_prologue(compiler *c, location loc)
 {
-    _PyCompile_CodeUnitMetadata umd = {
-        .u_posonlyargcount = 1,
-    };
-    RETURN_IF_ERROR(
-        codegen_enter_scope(c, name, COMPILE_SCOPE_ANNOTATIONS,
-                            key, loc.lineno, NULL, &umd));
-
     // if .format > VALUE_WITH_FAKE_GLOBALS: raise NotImplementedError
     PyObject *value_with_fake_globals = PyLong_FromLong(_Py_ANNOTATE_FORMAT_VALUE_WITH_FAKE_GLOBALS);
     if (value_with_fake_globals == NULL) {
@@ -737,6 +729,21 @@ codegen_setup_annotations_scope(compiler *c, location loc,
 }
 
 static int
+codegen_setup_annotations_scope(compiler *c, location loc,
+                                void *key, PyObject *name)
+{
+    _PyCompile_CodeUnitMetadata umd = {
+        .u_posonlyargcount = 1,
+    };
+    RETURN_IF_ERROR(
+        codegen_enter_scope(c, name, COMPILE_SCOPE_ANNOTATIONS,
+                            key, loc.lineno, NULL, &umd));
+
+    RETURN_IF_ERROR_IN_SCOPE(c, codegen_emit_annotations_prologue(c, loc));
+    return SUCCESS;
+}
+
+static int
 codegen_rename_annotations_format_param(PyCodeObject *co)
 {
     // We want the parameter to __annotate__ to be named "format" in the