Workflow consolidation:
- Delete integration.yml and daily-telemetry-e2e.yml (redundant with
  coverage workflow which already runs all e2e tests)
- Add push-to-main trigger to coverage workflow
- Run all tests (including telemetry) in single pytest invocation with
  --dist=loadgroup to respect xdist_group markers for isolation

Fix pyarrow cache:
- Remove cache-path: .venv-pyarrow from pyarrow jobs. Poetry always
  creates .venv regardless of the cache-path input, so the cache was
  never saved ("Path does not exist" error). The cache-suffix already
  differentiates keys between variants.

Fix 3.14 post-test DNS hang:
- Add enable_telemetry=False to unit test DUMMY_CONNECTION_ARGS that
  use server_hostname="foo". This prevents FeatureFlagsContext from
  making real HTTP calls to fake hosts, eliminating ~8min hang from
  ThreadPoolExecutor threads timing out on DNS on protected runners.

Improve e2e test parallelization:
- Split TestPySQLLargeQueriesSuite into 3 separate classes
  (TestPySQLLargeWideResultSet, TestPySQLLargeNarrowResultSet,
  TestPySQLLongRunningQuery) so xdist distributes them across workers
  instead of all landing on one.

Speed up slow tests:
- Reduce large result set sizes from 300MB to 100MB (still validates
  large fetches, lz4, chunking, row integrity)
- Start test_long_running_query at scale_factor=50 instead of 1 to
  skip ramp-up iterations that finish instantly

Co-authored-by: Isaac
Signed-off-by: Vikrant Puppala <vikrant.puppala@databricks.com>

- Use -n 4 instead of -n auto in coverage workflow. The e2e tests are
  network-bound (waiting on warehouse), not CPU-bound, so 4 workers on
  a 2-CPU runner is fine and doubles parallelism.
- Lower test_long_running_query min_duration from 3 min to 1 min.
  The test validates long-running query completion — 1 minute is
  sufficient and saves ~4 min per variant.
- Split lz4 on/off loop in test_query_with_large_wide_result_set into
  separate parametrized test cases so xdist can run them on different
  workers instead of sequentially in one test.

Co-authored-by: Isaac
Signed-off-by: Vikrant Puppala <vikrant.puppala@databricks.com>

Per review feedback from jprakash-db:
- Remove mixin classes (LargeWideResultSetMixin, etc) — inline the
  test methods directly into the test classes in test_driver.py
- Remove backward-compat LargeQueriesMixin alias (nothing uses it)
- Rename _LargeQueryRowHelper — replaced entirely by inlining
- Convert large_queries_mixin.py to just a fetch_rows() helper function

Co-authored-by: Isaac
Signed-off-by: Vikrant Puppala <vikrant.puppala@databricks.com>