refactor(blockifier): unavailable contract address error (#970)

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crates/blockifier/src/execution/deprecated_syscalls/deprecated_syscalls_test.rs

@@ -320,7 +320,7 @@ fn test_replace_class() {
 )]
 #[case::deploy_to_unavailable_address(
     true, true, false, true,
-    Some("is unavailable for deployment.".to_string())
+    Some("Deployment failed:".to_string())
     // With constructor, nontrivial calldata, address unavailable, deploy from zero; Negative flow.
 )]
 #[case::corrupt_deploy_from_zero(

crates/blockifier/src/execution/syscalls/syscall_tests/deploy.rs

@@ -176,5 +176,5 @@ fn to_unavailable_address(deployer_contract: FeatureContract) {
     entry_point_call.clone().execute_directly(&mut state).unwrap();
     let error = entry_point_call.execute_directly(&mut state).unwrap_err().to_string();
 
-    assert!(error.contains("is unavailable for deployment."));
+    assert!(error.contains("Deployment failed:"));
 }

crates/blockifier/src/state/errors.rs

@@ -19,7 +19,7 @@ pub enum StateError {
     OutOfRangeContractAddress,
     #[error(transparent)]
     ProgramError(#[from] ProgramError),
-    #[error("Requested {0:?} is unavailable for deployment.")]
+    #[error("Deployment failed: contract already deployed at address {:#064x}", ***.0)]
     UnavailableContractAddress(ContractAddress),
     #[error("Class with hash {:#064x} is not declared.", **.0)]
     UndeclaredClassHash(ClassHash),