tests: revert testing prerelease deps on Python 3.9

Consensus from today's meeting is that testing against prereleases needs to happen outside the normal presubmit path. Reverts only part of PR #479.
googleapis · Aug 17, 2021 · 431cde1 · 431cde1
1 parent 1f343a6
commit 431cde1
Showing 1 changed file with 0 additions and 2 deletions.
diff --git a/testing/constraints-3.9.txt b/testing/constraints-3.9.txt
@@ -1,2 +0,0 @@
-# Allow prerelease requirements
---pre