Bump ai to cf7d67f1e653cc9d8988ff0dc549eb7c357c3ef9

Changes:
```
> git log --format="%C(auto) %h %s" 47fa2fc..cf7d67f
 https://dart.googlesource.com/ai.git/+/cf7d67f create the working dir if it doesn't exist (147)

```

Diff: https://dart.googlesource.com/ai.git/+/47fa2fcf476a905b316282d9351e4ed063755ead..cf7d67f1e653cc9d8988ff0dc549eb7c357c3ef9/
Change-Id: Idd2a0b322cd36aea4c6b5555ee0ea621689bd7ca
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/431920
Reviewed-by: Devon Carew <[email protected]>
Commit-Queue: Devon Carew <[email protected]>
Auto-Submit: Jake Macdonald <[email protected]>
Commit-Queue: Jake Macdonald <[email protected]>

Author: jakemac53

DEPS

@@ -129,7 +129,7 @@ vars = {
   ### /third_party/pkg dependencies
   # 'tools/rev_sdk_deps.dart' will rev pkg dependencies to their latest; put an
   # EOL comment after a dependency to instead pin at the current revision.
-  "ai_rev": "47fa2fcf476a905b316282d9351e4ed063755ead",
+  "ai_rev": "cf7d67f1e653cc9d8988ff0dc549eb7c357c3ef9",
   "core_rev": "635dfa32c261ba078438b74de397f2207904ca78", # https://github.com/dart-lang/core/pull/734
   "dartdoc_rev": "8e6a95c4aba8def4ef01ccc600b3a3cfb8f3cb9e",
   "ecosystem_rev": "815d4ba2e7d11f8695a26f6cbe1262e3b8ff8d0d",