This commit increases the statement and branch coverage of the contracts
package. More specificall the contracts that were covered are:

- AddressDictator
- ChugSplashDictator
- L1CrossDomainMessenger
- L1StandardBridge
- CanonicalTransactionChain
- ChainStorageContainer
- StateCommitmentChain
- L2CrossDomainMessenger
- L2StandardBridge
- WETH9
- Lib_OVMCode
- Lib_RLPWriter
- Lib_SecureMerkleTrie
- Lib_Buffer
- Lib_MerkleTree