Nested classes are duplicated in generated testclass

[volivan239]

Description

Currently, codegen produces incorrect testclasses when there are nested classes in src code.

To Reproduce

Consider example:

public class OtherClass {
    public class InnerClass {
        private int y;
        InnerClass(int y) {
            this.y = y;
        }
        public class DeepInner {
            public int f() {
                if (y == 1) return 1;
                return 2;
            }
            public int f2() {
                return 0;
            }
        }
        public int g() {
            return 3;
        }
    }
    public int h() {
        return 4;
    }
}

1. Run tests for all methods from class OtherClass (currently you can do it in this branch)
2. Run tests for class DeepInner only.

Expected behavior

Correct tests are generated.

Actual behavior

1. class InnerClassTest is duplicated
2. main class is called OtherClass_InnerClass_DeepInnerTest, which does not correlate to file name DeepInnerTest.java, which causes compilation error.