Summaries are not generated for methods from nested classes of nested classes #710

Description

If we have a chain of at least three classes nested in each other (like class A { class B { class C { int f(); } } } ), summaries are not generated for the functions of the innermost of them (A.B.C.f() in our example).

To Reproduce

UPD. Nested classes are now supported in plugin, so the behavior can be reproduced just by launching plugin on the below class

As nested classes are currently supported only in contest estimator, the easiest way to reproduce the bug is through tests:

1. Add file DeepNested.java into utbot-sample/src/main/java/org/utbot/examples/inner/ with the following content:

package org.utbot.examples.inner;

public class DeepNested {
    public class Nested1 {
        public class Nested2 {
            public int f() {
                return 0;
            }
        }
    }
}

2. Add file DeepNestedTest.kt into utbot-summary-tests/src/test/kotlin/examples/inner/ with the following content:

package examples.inner

import examples.SummaryTestCaseGeneratorTest
import org.junit.jupiter.api.Test
import org.utbot.examples.DoNotCalculate
import org.utbot.examples.inner.DeepNested
import org.utbot.framework.plugin.api.MockStrategyApi

class DeepNestedTest : SummaryTestCaseGeneratorTest(
    DeepNested::class,
) {
    @Test
    fun testF() {
        val summary1 = "Test returns from: return 0;"

        val method = DeepNested.Nested1.Nested2::f
        val mockStrategy = MockStrategyApi.NO_MOCKS
        val coverage = DoNotCalculate

        val summaryKeys = listOf(
            summary1
        )

        summaryCheck(method, mockStrategy, coverage, summaryKeys)
    }
}

Expected behavior

Test passes, as corresponding summaries are generated for tests for A.B.C.f()

Actual behavior

Test fails because no summaries are generated.

Visual proofs (screenshots, logs, images)

Test fails with assertion message

The following comments were produced by the UTBot, but were not found in the list of comments passed in the check() method:

-------------------------------------------------------------

null-------------------------------------------------------------


The following comments were passed in the check() method, but were not found in the list of comments produced by the UTBot:

-------------------------------------------------------------

Test returns from: return 0;
-------------------------------------------------------------

Environment

Nothing specific.

Additional context

For me it seems that problem is in org.utbot.summary.ast.SourceCodeParser#traverseInnerClassDeclarations and the fact that it doesn't make any recursive calls.