Description

After introducing nullability and single type parameter for Kotlin code generation, static mocks became broken - they were no longer considered as BuiltinClassId, which means they were tried to load with default class loader which is impossible due to classes from mock frameworks could not be load with it.

This request makes mock classes builtin again - it fixes the problem but is incorrect for Kotlin code generation. The proper support of it should be designed and implemented together with generics in code generation (as planned in #88).

Fixes #981.

Type of Change

Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

Manual Scenario

Generating tests as mentioned in the issue.

Checklist:

• The change followed the style guidelines of the UTBot project
• Self-review of the code is passed
• The change contains enough commentaries, particularly in hard-to-understand areas
• New documentation is provided or existed one is altered
• No new warnings
• All tests pass locally with my changes