Refactor test_protocol.py

[crusaderky]

Move tests about compression from test_protocol.py to test_compression.py.
This is just a refactor; tests have not been changed.

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

       26 files  +         6         26 suites  +6   15h 53m 23s ⏱️ + 4h 33m 24s
  3 581 tests ±         0    3 473 ✔️ +       11     105 💤  -   10  3 ❌  - 1 
45 340 runs  +13 024  43 174 ✔️ +12 319  2 163 💤 +706  3 ❌  - 1 

For more details on these failures, see this check.

Results for commit f9fb3cf. ± Comparison against base commit f4f4718.

This pull request removes 44 and adds 44 tests. Note that renamed tests count towards both.

distributed.protocol.tests.test_protocol ‑ test_auto_compression
distributed.protocol.tests.test_protocol ‑ test_compression_1
distributed.protocol.tests.test_protocol ‑ test_compression_2
distributed.protocol.tests.test_protocol ‑ test_compression_3
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[None-bytes]
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[None-memoryview]
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[lz4-bytes]
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[lz4-memoryview]
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[snappy-bytes]
distributed.protocol.tests.test_protocol ‑ test_compression_thread_safety[snappy-memoryview]
…

distributed.protocol.tests.test_compression ‑ test_auto_compression
distributed.protocol.tests.test_compression ‑ test_compression_1
distributed.protocol.tests.test_compression ‑ test_compression_2
distributed.protocol.tests.test_compression ‑ test_compression_3
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[None-bytes]
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[None-memoryview]
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[lz4-bytes]
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[lz4-memoryview]
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[snappy-bytes]
distributed.protocol.tests.test_compression ‑ test_compression_thread_safety[snappy-memoryview]
…

♻️ This comment has been updated with latest results.