Remove unecessary code from Context (#2718)

contracts/utils/Context.sol

@@ -18,7 +18,6 @@ abstract contract Context {
     }
 
     function _msgData() internal view virtual returns (bytes calldata) {
-        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
         return msg.data;
     }
 }