Add fuzzing where possible #7515
Description
One of the code scanning alerts (https://github.com/quantumlib/Cirq/security/code-scanning/400) recommended the application of code fuzzing to help locate possible vulnerabilities in the code. We could use Google's OSS-Fuzz.
More info about OSS-Fuzz:
Google created OSS-Fuzz to fill this gap: it’s a free service that runs fuzzers for open source projects and privately alerts developers to the bugs detected. Since its launch, OSS-Fuzz has become a critical service for the open source community, growing beyond C/C++ to detect problems in memory-safe languages such as Go, Rust, and Python.
The OSS-Fuzz project has been adding AI-powered fuzzing, and is experimenting with AI-powered vulnerability fixing.