Update min_revision so that progression task can progress without err…

…ors (#4634)

If the min_revision (based on last_tested_crash_revision or
known_crash_revision) no longer exists, then use the first revision in
the list so that progression does not error out with "Build not found"

src/clusterfuzz/_internal/bot/tasks/utasks/progression_task.py

@@ -517,6 +517,15 @@ def find_fixed_range(uworker_input):
   known_crash_revision = last_tested_revision or testcase.crash_revision
   if not min_revision:
     min_revision = known_crash_revision
+    # If the min_revision (based on last_tested_crash_revision or
+    # known_crash_revision) no longer exists, then use the first
+    # revision in the list so that progression does not error out with
+    # "Build not found"
+    min_revision_in_list = revisions.get_first_revision_in_list(revision_list)
+    if min_revision < min_revision_in_list:
+      logs.info(f'Build {min_revision} might not exist in the list. Hence '
+                f'updating the min_revision to {min_revision_in_list}')
+      min_revision = min_revision_in_list
   if not max_revision:
     max_revision = revisions.get_last_revision_in_list(revision_list)