Supported assemble models for streams in concrete execution

[Damtev]

Description

For MUTs that return java,.util.stream.BaseStream concrete execution constructs UtCompositeModel of classes that implement stream interfaces - in JDK these classes are inheritors of java.util.stream.ReferencePipeline . These classes look very weird to the end user and require a lot of stuff to be constructed. The more acceptable way is constructing UtAssembleModels for streams with methods of and empty. This request adds support for such construction.

Type of Change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Automated Testing

org.utbot.examples.stream.StreamsAsMethodResultExampleTest

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
• New tests have been added
• All tests pass locally with my changes