Revert "Upgrade python to 3.11"

This reverts commit 6a167d1e1f.

Reason for revert: https://crbug.com/1511105

Original change's description:
> Upgrade python to 3.11
>
> R=bryner
>
> Bug: 1500415
> Change-Id: Ie379744131f7a9ced204a31f21079cb697c889a6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5030767
> Reviewed-by: Brian Ryner <bryner@google.com>
> Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>

Bug: 1500415
Change-Id: I8d0b04ca679c1581d4572e89efbb8cf2012cfa78
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5118878
Auto-Submit: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>

.vpython3

@@ -1,17 +1,17 @@
-python_version: "3.11"
+python_version: "3.8"
 
 # The default set of platforms vpython checks for does not yet include mac-arm64.
 # Setting `verify_pep425_tag` to the list of platforms we explicitly must support
 # allows us to ensure that vpython specs stay mac-arm64-friendly
 verify_pep425_tag: [
-    {python: "cp311", abi: "cp311", platform: "manylinux1_x86_64"},
-    {python: "cp311", abi: "cp311", platform: "linux_arm64"},
+    {python: "cp38", abi: "cp38", platform: "manylinux1_x86_64"},
+    {python: "cp38", abi: "cp38", platform: "linux_arm64"},
 
-    {python: "cp311", abi: "cp311", platform: "macosx_10_10_intel"},
-    {python: "cp311", abi: "cp311", platform: "macosx_11_0_arm64"},
+    {python: "cp38", abi: "cp38", platform: "macosx_10_10_intel"},
+    {python: "cp38", abi: "cp38", platform: "macosx_11_0_arm64"},
 
-    {python: "cp311", abi: "cp311", platform: "win32"},
-    {python: "cp311", abi: "cp311", platform: "win_amd64"}
+    {python: "cp38", abi: "cp38", platform: "win32"},
+    {python: "cp38", abi: "cp38", platform: "win_amd64"}
 ]
 
 # Used by:

bootstrap/manifest.txt

@@ -21,7 +21,7 @@ $VerifiedPlatform windows-amd64 windows-arm64 linux-amd64 mac-amd64 mac-arm64
 infra/3pp/tools/cpython/${platform} version:2@2.7.18.chromium.44
 
 @Subdir python3
-infra/3pp/tools/cpython3/${platform} version:2@3.11.6.chromium.30
+infra/3pp/tools/cpython3/${platform} version:2@3.8.10.chromium.26
 
 @Subdir git
 infra/3pp/tools/git/${platform} version:2@2.41.0.chromium.11

tests/gclient_eval_unittest.py

@@ -93,7 +93,7 @@ class GClientEvalTest(unittest.TestCase):
     def test_not_whitelisted(self):
         with self.assertRaises(ValueError) as cm:
             gclient_eval._gclient_eval('[x for x in [1, 2, 3]]')
-        self.assertIn('unexpected AST node: <ast.ListComp object',
+        self.assertIn('unexpected AST node: <_ast.ListComp object',
                       str(cm.exception))
 
     def test_dict_ordered(self):