Adapt the generated App Engine cron lexer and parser to system antlr3.
The Groc lexer and parser were generated using ANTLR 3.1.1 and rely on
legacy runtime APIs that are unavailable in antlr3-python-runtime 3.5.3.
Remove obsolete antlr3.compat imports and replace the generated
antlr_version attribute with api_version = 1 to satisfy the runtime's
version compatibility checks.
--- ../lib/googlecloudsdk/appengine/googlecron/GrocLexer.py	2026-10-19 13:37:49.454328728 +0300
+++ ../lib/googlecloudsdk/appengine/googlecron/GrocLexer.py	2026-10-19 13:38:38.088745100 +0300
@@ -14,7 +14,6 @@
 
 import sys
 from antlr3 import *
-from antlr3.compat import set, frozenset
 
 
 # for convenience in actions
@@ -67,9 +66,9 @@
 
 
 class GrocLexer(Lexer):
+    api_version = 1
 
     grammarFileName = "borg/borgcron/py/Groc.g"
-    antlr_version = version_str_to_tuple("3.1.1")
     antlr_version_str = "3.1.1"
 
     def __init__(self, input=None, state=None):
--- ../lib/googlecloudsdk/appengine/googlecron/GrocParser.py	2026-10-19 13:37:55.255388337 +0300
+++ ../lib/googlecloudsdk/appengine/googlecron/GrocParser.py	2026-10-19 13:39:14.412096261 +0300
@@ -14,7 +14,6 @@
 
 import sys
 from antlr3 import *
-from antlr3.compat import set, frozenset
 
 # Copyright 2005-2009 Google, Inc.  All rights reserved.
 # @author arb@google.com (Anthony Baxter)
@@ -117,8 +116,8 @@
 
 
 class GrocParser(Parser):
+    api_version = 1
     grammarFileName = "borg/borgcron/py/Groc.g"
-    antlr_version = version_str_to_tuple("3.1.1")
     antlr_version_str = "3.1.1"
     tokenNames = tokenNames