wip: parallel stateless fuzzing

[yash-atreya]

Motivation

Stacked on #11769

Solution

• Introduce SharedFuzzState which consists of global values of runs, timer, fail_fast and rejects to determine whether the fuzz test should_continue using the SharedFuzzState::should_continue
• Fuzz workers atomically update the values in SharedFuzzState

wip

TODO

• Add max_rejects in SharedFuzzState to track total rejects across workers and fail accordingly 40263fd
• Set failures in run_worker via SharedState::try_claim_failure - This will intercept other workers as well and stop fuzzing entirely e4c6060
• Introduce sync_interval for the WorkerCorpus and call WorkerCorpus::sync
• Determine number of workers - all available cores / --jobs
• Integrate into fn fuzz and run workers using rayon::IntoParallelIterator

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes