fix(c4-117-g12): splitting require() statements that use && saves gas

Signed-off-by: Tomás Migone <[email protected]>

Author: tmigone

contracts/gateway/L1GraphTokenGateway.sol

@@ -143,7 +143,8 @@ contract L1GraphTokenGateway is Initializable, GraphTokenGateway, L1ArbitrumMess
      * @param _escrow Address of the BridgeEscrow
      */
     function setEscrowAddress(address _escrow) external onlyGovernor {
-        require(_escrow != address(0) && Address.isContract(_escrow), "INVALID_ESCROW");
+        require(_escrow != address(0), "INVALID_ESCROW");
+        require(Address.isContract(_escrow), "MUST_BE_CONTRACT");
         escrow = _escrow;
         emit EscrowAddressSet(_escrow);
     }

contracts/upgrades/GraphProxy.sol

@@ -139,10 +139,8 @@ contract GraphProxy is GraphProxyStorage {
     function _acceptUpgrade() internal {
         address _pendingImplementation = _pendingImplementation();
         require(Address.isContract(_pendingImplementation), "Impl must be a contract");
-        require(
-            _pendingImplementation != address(0) && msg.sender == _pendingImplementation,
-            "Only pending implementation"
-        );
+        require(_pendingImplementation != address(0), "Impl cannot be zero address");
+        require(msg.sender == _pendingImplementation, "Only pending implementation");
 
         _setImplementation(_pendingImplementation);
         _setPendingImplementation(address(0));