Run testprojects integration tests with V2 test runner

[Eric-Arellano]

The V2 test runner does not support method level sharding, as V1 does. We cannot keep test_testprojects_integration.py as one single target because it would take far too long to run, and one single flake would mean every test would need to re-run.

Instead, we split up the target into multiple targets based on the source root, such as all antlr code getting its own test file.

This results in:

tests/python/pants_test/projects
├── BUILD
├── __init__.py
├── projects_test_base.py
├── test_antlr_projects_integration.py
├── test_java_examples_integration.py
├── test_java_testprojects_integration.py
├── test_maven_layout_integration.py
├── test_protobuf_projects_integration.py
├── test_python_examples_integration.py
├── test_python_testprojects_integration.py
├── test_scala_examples_integration.py
├── test_scala_testprojects_integration.py
├── test_thrift_projects_integration.py
└── test_wire_projects_integration.py

[stuhood]

Thanks!

[Eric-Arellano]

The last commit only modifies timeouts, which V2 currently ignores. Given the prior green run, merging.