With migration to pyest this fixture is useless. Removing and setting
the session to the module for the most of the tests.
Add dynamic_scope function to support running alternator fixtures in
session scope, while Test and TestSuite are not deleted. This is for
migration period, later on this function should be deleted.
Some test suites have own test runners based on pytest, and they
don't need all stuff we use for test.py. Move all code related to
test.py framework to test/pylib/runner.py and use it as a plugin
conditionally (by using TEST_RUNNER variable.)
There is the fixture in `test/cql/conftest.py` which checks
CQL connection after each test and exit from pytest session if
the connection was failed. For CQL tests it's simply no
difference what to use: pytest.exit() or pytest.fail() because
tests are executing one-by-one in separate pytest sessions.
Change it to pytest.fail() for future integration into a single
pytest session.
Create a custom pytest test collector for .cql files and
move CQL test execution logic from `CQLApprovalTest` class
and `pylib/cql_repl/cql_repl.py` file to `CqlTest.runtest()`
method.
In result, the only difference between CQLApproval and Python
suite types is suffixes of test files.
