tool: support reinitializer in slither-check-upgradeability

[QiuhaoLi]

Currently, the slither-check-upgradeability tool doesn't support the reinitializer in OZ's Initializable contract. For example, the CounterV2 below is a new implementation of Counter which adds a new storage variable and changed the changeX function:

// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.24;
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
contract Counter is Initializable {
    uint256 public x;

    function initialize(uint256 _x) public initializer {
        x = _x;
    }

    function changeX() public {
        x++;
    }
}

contract CounterV2 is Initializable {
    uint256 public x;
    uint256 public y;

    function initialize(uint256 _y) public reinitializer(2) {
        y = _y;
    }

    function changeX() public {
        x = x + y;
    }
}

Since slither-check-upgradeability can't recognize the reinitializer modifier, it will report a high-seveirity finding that the CounterV2.initialize(uint256) does not call the initializer modifier:

qiuhao@laptop:~/tmp/foundry_test/upgrade$ slither-check-upgradeability src/Counter.sol Counter --new-contract-name Counte
rV2
...
CounterV2.initialize(uint256) (src/Counter.sol#20-22) does not call the initializer modifier.
Reference: https://github.com/crytic/slither/wiki/Upgradeability-Checks#initializer-is-not-called

This PR supports the reinitializer modifier and fixes some tests for tests/tool/check_upgradeability.

[CLAassistant]

All committers have signed the CLA.

[0xalpharush]

This was merged as part of #2536