Experimental: Add Cloud Runner Interface for Executing Generated Fuzz Drivers

This PR introduces functionality to run fuzzing trials on fuzz drivers generated by various automated harnessing approaches. It is not intended to be merged into the main branch of oss-fuzz-gen, but instead serves as an interface for creating and executing fuzz tests using Google’s Cloud Runner and bucket infrastructure. Over the past few months, we have been collaborating with @DonggeLiu on a harnessing technique and are now preparing to scale up our broader fuzzing experiments. The core functionality is implemented in `run_driver.py` which uses a modified version of `builder_runner.py` to load the corresponding harness source into a Docker image and initiate fuzzing. This also operates on a version of oss-fuzz that is modified to be more compatible with afl-style fuzzing and coverage collection.