feat: add vm.skip(bool) (#410)

* feat: add vm.skip(bool)

* chore: dont name var like func name

Author: Evalir

src/Vm.sol

@@ -394,6 +394,8 @@ interface Vm is VmSafe {
     function deal(address account, uint256 newBalance) external;
     // Sets an address' code
     function etch(address target, bytes calldata newRuntimeBytecode) external;
+    // Marks a test as skipped. Must be called at the top of the test.
+    function skip(bool skipTest) external;
     // Expects an error on next call
     function expectRevert(bytes calldata revertData) external;
     function expectRevert(bytes4 revertData) external;