Handle change related reqs on push like events

Push and ref-updated events do not have an associated change or
pull-request. Thus, requirements that are specific to changes or
pull-requests cannot possibly be met.

To make this work, Ref filters should only be applied to changes that
come from a matching connection. This was not previously enforced when
filters became connection specific.

Change-Id: I5d67bef264db0ad5ba3a7180ce74e3670ba822ce
Story: 2000774
Task: 4624
diff --git a/tests/fixtures/config/push-reqs/main.yaml b/tests/fixtures/config/push-reqs/main.yaml
new file mode 100644
index 0000000..d9f1a42
--- /dev/null
+++ b/tests/fixtures/config/push-reqs/main.yaml
@@ -0,0 +1,11 @@
+- tenant:
+    name: tenant-one
+    source:
+      github:
+        config-projects:
+          - common-config
+        untrusted-projects:
+          - org/project1
+      gerrit:
+        untrusted-projects:
+          - org/project2