contracts-bedrock: delete dead file

packages/contracts-bedrock/test/Helpers.sol

-// SPDX-License-Identifier: MIT
-pragma solidity ^0.8.0;
-
-contract CallRecorder {
-    struct CallInfo {
-        address sender;
-        bytes data;
-        uint256 gas;
-        uint256 value;
-    }
-
-    CallInfo public lastCall;
-
-    function record() public payable {
-        lastCall.sender = msg.sender;
-        lastCall.data = msg.data;
-        lastCall.gas = gasleft();
-        lastCall.value = msg.value;
-    }
-}
-
-contract Reverter {
-    function doRevert() public pure {
-        revert("Reverter reverted");
-    }
-}