Pants CI: Run all unit and pack tests #5383

Job	Run time
Skip Duplicate Jobs Pre Job	4s
Lint Checks (black, flake8, etc.) - Python 3.8	2m 1s
Unit Tests (chunk 1) - Python 3.8	6m 5s
Compile (pip deps, pylint, etc.) - Python 3.8	3m 23s
Unit Tests (chunk 2) - Python 3.8	4m 59s
Pack Tests - Python 3.8	2m 52s
Lint Checks (black, flake8, etc.) - Python 3.9	2m 13s
Unit Tests (chunk 1) - Python 3.9	6m 20s
Integration Tests (chunk 1) - Python 3.8	5m 10s
Compile (pip deps, pylint, etc.) - Python 3.9	3m 12s
Self-check on Python 3.8 - Python 3.8	7m 57s
Unit Tests (chunk 2) - Python 3.9	6m 4s
Integration Tests (chunk 2) - Python 3.8	6m 21s
Pack Tests - Python 3.9	2m 45s
Integration Tests (chunk 1) - Python 3.9	5m 40s
Integration Tests (chunk 2) - Python 3.9	6m 23s
Slack notification for failed master builds	5s
	1h 11m 34s

Provide feedback