test: remove testFail* tests (#643)

In preparation to deprecate `testFail*`:
foundry-rs/foundry#9574

- Removes `deployMockERC721` and `deployMockERC20` from `StdUtils` as
their tests includes large amount of `testFail*` tests and is generally
outdated. I haven't been able to find the `deploy*` methods being used
in any public project on Github.
- Implements workaround for other cases

Alternatively we could upstream Solady's mocks and tests (which have
been updated to not use `testFail*` but this feels out of place and
would be incomplete (ERC4626, ERC6909, etc..
https://github.com/Vectorized/solady/tree/main/test/utils/mocks). I
think it is most common for people to rely on the mocks their library
comes with (be it Solmate, Solady or OpenZeppelin) or write their own
wrapper around the token implementation.

src/StdUtils.sol

@@ -4,8 +4,6 @@ pragma solidity >=0.6.2 <0.9.0;
 pragma experimental ABIEncoderV2;
 
 import {IMulticall3} from "./interfaces/IMulticall3.sol";
-import {MockERC20} from "./mocks/MockERC20.sol";
-import {MockERC721} from "./mocks/MockERC721.sol";
 import {VmSafe} from "./Vm.sol";
 
 abstract contract StdUtils {
@@ -119,21 +117,6 @@ abstract contract StdUtils {
         return vm.computeCreate2Address(salt, initCodeHash);
     }
 
-    /// @dev returns an initialized mock ERC20 contract
-    function deployMockERC20(string memory name, string memory symbol, uint8 decimals)
-        internal
-        returns (MockERC20 mock)
-    {
-        mock = new MockERC20();
-        mock.initialize(name, symbol, decimals);
-    }
-
-    /// @dev returns an initialized mock ERC721 contract
-    function deployMockERC721(string memory name, string memory symbol) internal returns (MockERC721 mock) {
-        mock = new MockERC721();
-        mock.initialize(name, symbol);
-    }
-
     /// @dev returns the hash of the init code (creation code + no args) used in CREATE2 with no constructor arguments
     /// @param creationCode the creation code of a contract C, as returned by type(C).creationCode
     function hashInitCode(bytes memory creationCode) internal pure returns (bytes32) {