Refactor TokenBridge to use transient storage for the ReentrancyGuard implementation

[kyzooghost]

Description

Refactor TokenBridge to use transient storage for the ReentrancyGuard implementation. Existing ReentrancyGuard implementation using transient storage exist in:

• TransientStorageReentrancyGuardUpgradeable.sol
• https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/ReentrancyGuardTransient.sol

Note that transient storage is only available from Cancun, and currently all our L2 contracts are compiled for London. This is because we can generate ZK proofs for execution traces using London EVM rules.

Motivation

More gas efficient implementation of ReentrancyGuard

Tasks

• Refactor TokenBridge to use transient storage for the ReentrancyGuard implementation

Acceptance criteria

• Passing unit test for new implementation of ReentrancyGuard

Risks

If we compile the TokenBridge with EVM_VERSION: cancun, then we should eventually compile all L2 contracts with EVM_VERSION: cancun to minimize version skew. If however the prover is then unable to generate proofs of Cancun EVM execution, then finalization of L2->L1 messages should fail. The E2E tests should capture this.

• E2E tests will break if provers are unable to generate proofs of Cancun EVM execution
• Version skew of L2 contracts - some L2 contracts compile in London, other L2 contracts compile in Cancun
• Upgrades of deployed contracts should not occur without i.) No version skew, ii.) provers being able to generate Cancun EVM execution proofs

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