Fix tests on upgradeable contracts after transpilation

Author: frangio

contracts/mocks/crosschain/bridges.sol

@@ -41,7 +41,9 @@ contract BridgeAMBMock is BaseRelayMock {
  * Arbitrum
  */
 contract BridgeArbitrumL1Mock is BaseRelayMock {
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
     address public immutable inbox = address(new BridgeArbitrumL1Inbox());
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
     address public immutable outbox = address(new BridgeArbitrumL1Outbox());
 
     function activeOutbox() public view returns (address) {
@@ -54,10 +56,12 @@ contract BridgeArbitrumL1Mock is BaseRelayMock {
 }
 
 contract BridgeArbitrumL1Inbox {
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
     address public immutable bridge = msg.sender;
 }
 
 contract BridgeArbitrumL1Outbox {
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
     address public immutable bridge = msg.sender;
 
     function l2ToL1Sender() public view returns (address) {

contracts/mocks/crosschain/receivers.sol

@@ -9,10 +9,14 @@ import "../../crosschain/arbitrum/CrossChainEnabledArbitrumL2.sol";
 import "../../crosschain/optimism/CrossChainEnabledOptimism.sol";
 import "../../crosschain/polygon/CrossChainEnabledPolygonChild.sol";
 
-abstract contract Receiver is Ownable, CrossChainEnabled {
+abstract contract Receiver is CrossChainEnabled {
+    // we don't use Ownable because it messes up testing for the upgradeable contracts
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
+    address public immutable owner = msg.sender;
+
     function crossChainRestricted() external onlyCrossChain {}
 
-    function crossChainOwnerRestricted() external onlyCrossChainSender(owner()) {}
+    function crossChainOwnerRestricted() external onlyCrossChainSender(owner) {}
 }
 
 /**