Fix missing outputs for jobs with matrix (#32823)

Fix #32795

If a job uses a matrix, multiple `ActionRunJobs` may have the same
`JobID`. We need to merge the outputs of these jobs to make them
available to the jobs that need them.

routers/api/actions/runner/main_test.go

@@ -0,0 +1,14 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package runner
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/unittest"
+)
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m)
+}