cannon: remove old test-util preimage-cheat function

cannon/mipsevm/evm.go

@@ -25,7 +25,6 @@ import (
 
 var (
 	StepBytes4                      = crypto.Keccak256([]byte("step(bytes,bytes)"))[:4]
-	CheatBytes4                     = crypto.Keccak256([]byte("cheat(uint256,bytes32,bytes32,uint256)"))[:4]
 	LoadKeccak256PreimagePartBytes4 = crypto.Keccak256([]byte("loadKeccak256PreimagePart(uint256,bytes)"))[:4]
 	LoadLocalDataBytes4             = crypto.Keccak256([]byte("loadLocalData(uint256,bytes32,uint256,uint256)"))[:4]
 )

packages/contracts-bedrock/.gas-snapshot

@@ -532,8 +532,8 @@ OptimistTest:test_tokenURI_returnsCorrectTokenURI_succeeds() (gas: 195908)
 OptimistTest:test_transferFrom_soulbound_reverts() (gas: 75512)
 PreimageOracle_Test:test_keccak256PreimageKey_succeeds() (gas: 319)
 PreimageOracle_Test:test_loadKeccak256PreimagePart_outOfBoundsOffset_reverts() (gas: 8993)
-PreimageOracle_Test:test_loadKeccak256PreimagePart_succeeds() (gas: 76098)
-PreimageOracle_Test:test_loadLocalData_onePart_succeeds() (gas: 75840)
+PreimageOracle_Test:test_loadKeccak256PreimagePart_succeeds() (gas: 76076)
+PreimageOracle_Test:test_loadLocalData_onePart_succeeds() (gas: 75818)
 PreimageOracle_Test:test_loadLocalData_outOfBoundsOffset_reverts() (gas: 8803)
 ProtocolVersions_Initialize_Test:test_initialize_events_succeeds() (gas: 52175)
 ProtocolVersions_Initialize_Test:test_initialize_values_succeeds() (gas: 32301)

packages/contracts-bedrock/src/cannon/PreimageOracle.sol

@@ -31,17 +31,6 @@ contract PreimageOracle is IPreimageOracle {
         dat_ = preimageParts[_key][_offset];
     }
 
-    /// TODO(CLI-4104):
-    /// we need to mix-in the ID of the dispute for local-type keys to avoid collisions,
-    /// and restrict local pre-image insertion to the dispute-managing contract.
-    /// For now we permit anyone to write any pre-image unchecked, to make testing easy.
-    /// This method is DANGEROUS. And NOT FOR PRODUCTION.
-    function cheat(uint256 partOffset, bytes32 key, bytes32 part, uint256 size) external {
-        preimagePartOk[key][partOffset] = true;
-        preimageParts[key][partOffset] = part;
-        preimageLengths[key] = size;
-    }
-
     /// @inheritdoc IPreimageOracle
     function loadLocalData(
         uint256 _ident,