Make candidate validation timeouts configurable (#4001)

* pvf: make execution timeout configurable

* guide: add timeouts to candidate validation params

* add timeouts to candidate validation messages

* fmt

* port backing to use the backing pvf timeout

* port approval-voting to use the execution timeout

* port dispute participation to use the correct timeout

* fmt

* address grumbles & test failure

polkadot/node/core/candidate-validation/src/tests.rs

@@ -341,6 +341,7 @@ impl ValidationBackend for MockValidatorBackend {
 	async fn validate_candidate(
 		&mut self,
 		_raw_validation_code: Vec<u8>,
+		_timeout: Duration,
 		_params: ValidationParams,
 	) -> Result<WasmValidationResult, ValidationError> {
 		self.result.clone()
@@ -384,6 +385,7 @@ fn candidate_validation_ok_is_ok() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	))
 	.unwrap();
@@ -426,6 +428,7 @@ fn candidate_validation_bad_return_is_invalid() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	))
 	.unwrap();
@@ -461,6 +464,7 @@ fn candidate_validation_timeout_is_internal_error() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	));
 
@@ -495,6 +499,7 @@ fn candidate_validation_code_mismatch_is_invalid() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	))
 	.unwrap();
@@ -534,6 +539,7 @@ fn compressed_code_works() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	));
 
@@ -573,6 +579,7 @@ fn code_decompression_failure_is_invalid() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	));
 
@@ -613,6 +620,7 @@ fn pov_decompression_failure_is_invalid() {
 		validation_code,
 		descriptor,
 		Arc::new(pov),
+		Duration::from_secs(0),
 		&Default::default(),
 	));