Try two-stage testing in Sippy, version #1 (openshift#68555)

Non-pipelined version, autorun false, but not optional on e2e.

Author: stbenjam

ci-operator/config/openshift/sippy/openshift-sippy-main.yaml

@@ -30,7 +30,8 @@ tests:
   commands: HOME=/tmp make lint
   container:
     from: src
-- as: e2e
+- always_run: false
+  as: e2e
   cluster_claim:
     architecture: amd64
     as: latest

ci-operator/jobs/openshift/sippy/openshift-sippy-main-presubmits.yaml

@@ -57,7 +57,7 @@ presubmits:
           secretName: result-aggregator
     trigger: (?m)^/test( | .* )build,?($|\s.*)
   - agent: kubernetes
-    always_run: true
+    always_run: false
     branches:
     - ^main$
     - ^main-
@@ -124,7 +124,7 @@ presubmits:
       - name: result-aggregator
         secret:
           secretName: result-aggregator
-    trigger: (?m)^/test( | .* )e2e,?($|\s.*)
+    trigger: (?m)^/test( | .* )(e2e|remaining-required),?($|\s.*)
   - agent: kubernetes
     always_run: true
     branches: