Make progression a UTask (#3643)

Progression will be hard to combine tasks into jobs because there's so
many of them that are started by a single instance.
Instead, just create each batch job. This should work according to my
math because progression runs 3-6X less often than variant.

Author: jonathanmetzman

src/clusterfuzz/_internal/bot/tasks/task_types.py

@@ -187,7 +187,7 @@ def execute(self, task_argument, job_type, uworker_env):
     'fuzz': UTaskLocalExecutor,
     'impact': TrustedTask,
     'minimize': UTaskLocalExecutor,
-    'progression': UTaskLocalExecutor,
+    'progression': UTaskCombined,
     'regression': UTaskLocalExecutor,
     'symbolize': UTaskCombined,
     'unpack': TrustedTask,