See #104431 (comment)
This is the CI build: https://ci.chromium.org/ui/p/flutter/builders/try/Mac%20customer_testing/31608/overview
Here are the relevant logs:
From https://github.com/flutter/flutter
* [new branch] master -> master
* [new branch] master -> origin/master
Warning: you are leaving 1 commit behind, not connected to
any of your branches:
19204c238e Roll engine to d882b2d12375a4ae54baeccd2f7b0aafef422831
Switched to branch 'master'
+ dart __deprecated_pub get
Downloading Darwin x64 Dart SDK from Flutter engine 1bfe551d6b5adec64bb677cbb31ffd56c5acff49...
Building flutter tool...
Exhausted heap space, trying to allocate 32 bytes.
Note the engine version is from upstream HEAD, not the PR
This means that if upstream master Flutter SDK is broken, this CI test will have to be broken, even if run on a PR that would have fixed it