Consider supporting Foundry's invariant testing

[palinatolmach]

Based on a post-workshop EthCC question @JuanCoRo got asked; will move it to backlog for now.

We might consider supporting Foundry's invariant tests, which executes function call sequences in an attempt to break an invariant specified as a function, e.g.,

function invariant_job1() public {
   assertInvariants();
}

function invariant_job2() public {
   assertInvariants();
}

function assertInvariants() internal {
   assertEq(val1, val2);
   assertEq(val3, val4);
}

That is something we could do using symbolic execution (modulo path and configuration explosion).