Engine sets the hidden SecurityManager static field #697

Description

Engine produces staticsBefore with the hidden SecurityManager static field. The concrete executor can't find this field, so it isn't present in staticsAfter. This leads to test generation failure as we expect staticsBefore and staticsAfter to have the same structure.

To Reproduce

Steps to reproduce the behavior:

1. Create this method:

    public void createThread() {
        final int[] x = {0};
        new Thread(() -> {
            x[0]++;
        }).start();
        new Thread(() -> {
            x[0]++;
        }).start();
    }

2. Run test generation via UtBot plugin

Expected behavior

At least one test generated and there are no tests with internal exceptions.

Actual behavior

There is a generated test with an internal exception.

Visual proofs (screenshots, logs, images)