Executor: test Tx_count limit with incorrect tx source (#2242)

## Linked Issues/PRs
<!-- List of related issues/PRs -->

Closes #2225

## Description
<!-- List of detailed changes -->

As per discussion, we should check that the current Executor logic is
resilient against transactions source that ignore the limit on
MAX_TX_COUNT.

## Checklist
- [ ] New behavior is reflected in tests


### Before requesting review
- [ ] I have reviewed the code myself

---------

Co-authored-by: Green Baneling <[email protected]>

crates/fuel-core/src/executor.rs

@@ -3,6 +3,9 @@
 #[allow(non_snake_case)]
 #[cfg(test)]
 mod tests {
+
+    use std::sync::Mutex;
+
     use crate as fuel_core;
     use fuel_core::database::Database;
     use fuel_core_executor::{
@@ -13,6 +16,7 @@ mod tests {
         ports::{
             MaybeCheckedTransaction,
             RelayerPort,
+            TransactionsSource,
         },
         refs::ContractRef,
     };
@@ -183,6 +187,32 @@ mod tests {
         }
     }
 
+    /// Bad transaction source: ignores the limit of `u16::MAX -1` transactions
+    /// that should be returned by [`TransactionsSource::next()`].
+    /// It is used only for testing purposes
+    pub struct BadTransactionsSource {
+        transactions: Mutex<Vec<MaybeCheckedTransaction>>,
+    }
+
+    impl BadTransactionsSource {
+        pub fn new(transactions: Vec<Transaction>) -> Self {
+            Self {
+                transactions: Mutex::new(
+                    transactions
+                        .into_iter()
+                        .map(MaybeCheckedTransaction::Transaction)
+                        .collect(),
+                ),
+            }
+        }
+    }
+
+    impl TransactionsSource for BadTransactionsSource {
+        fn next(&self, _: u64, _: u16, _: u32) -> Vec<MaybeCheckedTransaction> {
+            std::mem::take(&mut *self.transactions.lock().unwrap())
+        }
+    }
+
     fn add_consensus_parameters(
         mut database: Database,
         consensus_parameters: &ConsensusParameters,
@@ -3022,6 +3052,51 @@ mod tests {
         );
     }
 
+    #[test]
+    fn block_producer_never_includes_more_than_max_tx_count_transactions_with_bad_tx_source(
+    ) {
+        let block_height = 1u32;
+        let block_da_height = 2u64;
+
+        let mut consensus_parameters = ConsensusParameters::default();
+
+        // Given
+        let transactions_in_tx_source = (MAX_TX_COUNT as usize) + 10;
+        consensus_parameters.set_block_gas_limit(u64::MAX);
+        let config = Config {
+            consensus_parameters,
+            ..Default::default()
+        };
+
+        let block = test_block(
+            block_height.into(),
+            block_da_height.into(),
+            transactions_in_tx_source,
+        );
+        let partial_fuel_block: PartialFuelBlock = block.into();
+        let components = Components {
+            header_to_produce: partial_fuel_block.header,
+            transactions_source: BadTransactionsSource::new(
+                partial_fuel_block.transactions,
+            ),
+            coinbase_recipient: Default::default(),
+            gas_price: 0,
+        };
+
+        // When
+        let producer = create_executor(Database::default(), config);
+        let (result, _) = producer
+            .produce_without_commit_with_source(components)
+            .unwrap()
+            .into();
+
+        // Then
+        assert_eq!(
+            result.block.transactions().len(),
+            (MAX_TX_COUNT as usize + 1)
+        );
+    }
+
     #[cfg(feature = "relayer")]
     mod relayer {
         use super::*;