Add WPT for CSP with trailing dot in hostname

This CL adds a generic WPT test to make sure hosts with trailing dots
can be defined in CSP.
The CL targets connect-src directive as a proof of concept. More
tests can be added for other directives later on.

Bug: 1512075
Change-Id: Ia3d8ec4c4b6594d46ff6c65ff8275bfd6bdd70fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5185382
Reviewed-by: Antonio Sartori <antoniosartori@chromium.org>
Commit-Queue: Saeid Eid <saeideid@chromium.org>
Reviewed-by: Jonathan Hao <phao@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1246451}

content-security-policy/generic/src-trailing-dot.sub.any.js

@@ -0,0 +1,6 @@
+// META: global=window,worker
+
+promise_test(t => {
+    return fetch("{{location[scheme]}}://{{host}}.:{{location[port]}}"
+        + "/content-security-policy/support/resource.py");
+}, "Fetch from host with trailing dot should be allowed by CSP.");

content-security-policy/generic/src-trailing-dot.sub.any.js.sub.headers

@@ -0,0 +1 @@
+Content-Security-Policy: connect-src {{location[scheme]}}://{{host}}.:{{location[port]}}