fix(l2): race conditions in ERC20 integration tests (#6138)

**Motivation**

The L2 integration test workflow failed in [this
run](https://github.com/lambdaclass/ethrex/actions/runs/21723329010/job/62659573593)
with `l2_balance == 0` instead of the expected `100`. This may be caused
by two possible race conditions.

**Description**

**Fix 1: Nonce race condition in `create_deploy`**
(`crates/l2/sdk/src/sdk.rs`)

The contract address was computed from a nonce fetched *after* sending
the deploy transaction. If the transaction was mined before the nonce
query returned, `get_nonce` would return N+1 instead of N, resulting in
an incorrect contract address. The test would then use the wrong address
for the ERC20 deposit, causing the bridge's `mintERC20` to silently fail
(it uses `call()` and falls back to `_withdraw` instead of reverting).

Fix: Use `receipt.tx_info.contract_address` from the transaction receipt
instead of computing it from the nonce.

**Fix 2: Compile race condition in integration tests**
(`test/tests/l2/integration_tests.rs`)

Both ERC20 tests compile `L2ERC20.sol` to the same output file
(`solc_out/TestTokenL2.bin`). When running concurrently via `JoinSet`,
one test could read partially written bytecode from the other test's
compilation.

Fix: Each test now compiles to its own output directory
(`test_erc20_roundtrip/` and `test_erc20_mismatch/`).

**Checklist**

- [ ] Updated `STORE_SCHEMA_VERSION` (crates/storage/lib.rs) if the PR
includes breaking changes to the `Store` requiring a re-sync.

Author: avilagaston9

crates/l2/sdk/src/sdk.rs

@@ -444,18 +444,11 @@ pub async fn create_deploy(
     .await?;
     let deploy_tx_hash = send_generic_transaction(client, deploy_tx, deployer).await?;
 
-    let nonce = client
-        .get_nonce(deployer.address(), BlockIdentifier::Tag(BlockTag::Latest))
-        .await?;
-    let mut encode = vec![];
-    (deployer.address(), nonce).encode(&mut encode);
-
-    //Taking the last 20bytes so it matches an H160 == Address length
-    let deployed_address = Address::from_slice(keccak(encode).as_fixed_bytes().get(12..).ok_or(
-        EthClientError::Custom("Failed to get deployed_address".to_owned()),
-    )?);
+    let receipt = wait_for_transaction_receipt(deploy_tx_hash, client, 1000).await?;
 
-    wait_for_transaction_receipt(deploy_tx_hash, client, 1000).await?;
+    let deployed_address = receipt.tx_info.contract_address.ok_or_else(|| {
+        EthClientError::Custom("Deploy transaction did not create a contract".to_owned())
+    })?;
 
     Ok((deploy_tx_hash, deployed_address))
 }

test/tests/l2/integration_tests.rs

@@ -562,6 +562,7 @@ async fn test_erc20_roundtrip(
     let token_l1 = test_deploy_l1(&l1_client, &init_code_l1, &rich_wallet_private_key).await?;
 
     let contracts_path = workspace_root().join("crates/l2/contracts");
+    let compile_output_path = contracts_path.join("test_erc20_roundtrip");
 
     get_contract_dependencies(&contracts_path);
     let remappings = [(
@@ -570,7 +571,7 @@ async fn test_erc20_roundtrip(
             .join("lib/openzeppelin-contracts-upgradeable/lib/openzeppelin-contracts/contracts"),
     )];
     compile_contract(
-        &contracts_path,
+        &compile_output_path,
         &contracts_path.join("src/example/L2ERC20.sol"),
         false,
         false,
@@ -579,7 +580,7 @@ async fn test_erc20_roundtrip(
         None,
     )?;
     let init_code_l2_inner = hex::decode(String::from_utf8(std::fs::read(
-        contracts_path.join("solc_out/TestTokenL2.bin"),
+        compile_output_path.join("solc_out/TestTokenL2.bin"),
     )?)?)?;
     let init_code_l2 = [
         init_code_l2_inner,
@@ -783,6 +784,7 @@ async fn test_erc20_withdraw_l1_address_mismatch(
     let token_l1 = test_deploy_l1(&l1_client, &init_code_l1, &rich_wallet_private_key).await?;
 
     let contracts_path = workspace_root().join("crates/l2/contracts");
+    let compile_output_path = contracts_path.join("test_erc20_mismatch");
 
     get_contract_dependencies(&contracts_path);
     let remappings = [(
@@ -791,7 +793,7 @@ async fn test_erc20_withdraw_l1_address_mismatch(
             .join("lib/openzeppelin-contracts-upgradeable/lib/openzeppelin-contracts/contracts"),
     )];
     compile_contract(
-        &contracts_path,
+        &compile_output_path,
         &contracts_path.join("src/example/L2ERC20.sol"),
         false,
         false,
@@ -800,7 +802,7 @@ async fn test_erc20_withdraw_l1_address_mismatch(
         None,
     )?;
     let init_code_l2_inner = hex::decode(String::from_utf8(std::fs::read(
-        contracts_path.join("solc_out/TestTokenL2.bin"),
+        compile_output_path.join("solc_out/TestTokenL2.bin"),
     )?)?)?;
     let init_code_l2 = [
         init_code_l2_inner,