Set up CIFuzz to run fuzz targets continuously

[illia-v]

Feature or enhancement

OSS-Fuzz offers CIFuzz, a collection of GitHub actions that can be used for running fuzz targets based on the existing OSS-Fuzz configuration similarly to running unit tests in CI.

Pitch

CPython has been tested by OSS-Fuzz for a few years. The tool has helped discover multiple issues like #91466, #102509, and #106057. However, there is a tendency to leave builds or individual tests broken for a while. The issues are usually caused by changes in CPython code, and current testing performed in GitHub actions and Buildbot misses some cases like compiling CPython with memory sanitizer.

CIFuzz can help identify issues when they are created, and passing tests can be made a requirement for a successful status of a pull request. This can help prevent new issues of this kind from being merged in the main branch.

Linked PRs

• gh-107652: Set up CIFuzz to run fuzz targets continuously #107653