Prevent static runners from terminating due to unregister timeout

The unregister timeout of 1 minute (no matter how long it is) can negatively impact availability of static runner constantly running workflow jobs, and ephemeral runner that runs a long-running job.
We deal with that by completely removing the unregistaration timeout, so that regarldess of the type of runner(static or ephemeral) it waits forever until it successfully to get unregistered before being terminated.

test/e2e/e2e_test.go

@@ -186,6 +186,7 @@ type env struct {
 	runnerLabel, githubToken, testRepo, testOrg, testOrgRepo string
 	githubTokenWebhook                                       string
 	testEnterprise                                           string
+	testEphemeral                                            string
 	featureFlagEphemeral                                     *bool
 	scaleDownDelaySecondsAfterScaleOut                       int64
 	minReplicas                                              int64
@@ -219,7 +220,8 @@ func initTestEnv(t *testing.T) *env {
 	e.testOrg = testing.Getenv(t, "TEST_ORG", "")
 	e.testOrgRepo = testing.Getenv(t, "TEST_ORG_REPO", "")
 	e.testEnterprise = testing.Getenv(t, "TEST_ENTERPRISE")
-	e.testJobs = createTestJobs(id, testResultCMNamePrefix, 100)
+	e.testEphemeral = testing.Getenv(t, "TEST_EPHEMERAL", "")
+	e.testJobs = createTestJobs(id, testResultCMNamePrefix, 20)
 
 	if ephemeral, err := strconv.ParseBool(testing.Getenv(t, "TEST_FEATURE_FLAG_EPHEMERAL", "")); err == nil {
 		e.featureFlagEphemeral = &ephemeral
@@ -288,6 +290,7 @@ func (e *env) installActionsRunnerController(t *testing.T) {
 		"WEBHOOK_GITHUB_TOKEN=" + e.githubTokenWebhook,
 		"RUNNER_LABEL=" + e.runnerLabel,
 		"TEST_ID=" + e.testID,
+		"TEST_EPHEMERAL=" + e.testEphemeral,
 		fmt.Sprintf("RUNNER_SCALE_DOWN_DELAY_SECONDS_AFTER_SCALE_OUT=%d", e.scaleDownDelaySecondsAfterScaleOut),
 		fmt.Sprintf("REPO_RUNNER_MIN_REPLICAS=%d", e.minReplicas),
 		fmt.Sprintf("ORG_RUNNER_MIN_REPLICAS=%d", e.minReplicas),