Use CPU clock timeout for PVF jobs (#6282)

* Put in skeleton logic for CPU-time-preparation

Still needed:
- Flesh out logic
- Refactor some spots
- Tests

* Continue filling in logic for prepare worker CPU time changes

* Fix compiler errors

* Update lenience factor

* Fix some clippy lints for PVF module

* Fix compilation errors

* Address some review comments

* Add logging

* Add another log

* Address some review comments; change Mutex to AtomicBool

* Refactor handling response bytes

* Add CPU clock timeout logic for execute jobs

* Properly handle AtomicBool flag

* Use `Ordering::Relaxed`

* Refactor thread coordination logic

* Fix bug

* Add some timing information to execute tests

* Add section about the mitigation to the IG

* minor: Change more `Ordering`s to `Relaxed`

* candidate-validation: Fix build errors

polkadot/node/core/pvf/Cargo.toml

@@ -13,6 +13,7 @@ always-assert = "0.1"
 async-std = { version = "1.11.0", features = ["attributes"] }
 async-process = "1.3.0"
 assert_matches = "1.4.0"
+cpu-time = "1.0.0"
 futures = "0.3.21"
 futures-timer = "3.0.2"
 slotmap = "1.0"
@@ -21,10 +22,13 @@ pin-project = "1.0.9"
 rand = "0.8.5"
 tempfile = "3.3.0"
 rayon = "1.5.1"
+
 parity-scale-codec = { version = "3.1.5", default-features = false, features = ["derive"] }
+
 polkadot-parachain = { path = "../../../parachain" }
 polkadot-core-primitives = { path = "../../../core-primitives" }
 polkadot-node-metrics = { path = "../../metrics"}
+
 sc-executor = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-executor-wasmtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-executor-common = { git = "https://github.com/paritytech/substrate", branch = "master" }