Test generation fails if any unexpected exception occurs for a single method

[Markoutte]

Description

When generate a test case if unexpected error occurs for a single method it cancels test generation for whole class.

To Reproduce

1. IntelliJ IDEA 2022.1.4 with installed plugin is opened.
2. Go to File -> Settings -> Tools -> UtBot
3. Set Code analysis slider somewhere in the middle.
4. Set Mock strategy to Other packages: Mockito, click OK
5. Add a class with the following code

    public String property(String key) {
        return System.getProperty(key);
    }

6. Generate tests for it with Mock strategy for Other packages / classes

Expected behavior

The bad test attempts should be passed (but logged) to recognize the problem, but not breaking the output.

Actual behavior

No test generated if symbolic engine is on.

Additional context

The symbolic execution fails for this test after #622 is implemented.

If only fuzzing works the test set is generated normally.