ci: Update virtio-villain to v0.6.4

Bump the pinned virtio-villain tag to v0.6.4. This release fixes
runtime behavior in the batch runner so it no longer reports spurious
WEDGED when a batch times out or a VMM writes to stderr.

With those fixes and the new retries flag the excludes for the flaky
tests are no longer needed and are dropped. A flaky failure is retried
a couple of times rather than suppressed, while a consistent failure
still surfaces. This mimics the nextest approach.

It also adds a large batch of block and net conformance tests, so the
run covers more of the device model.

Assisted-by: Claude:Opus-4.8
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

.github/workflows/ci.yaml

@@ -854,7 +854,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       VILLAIN_REPO: https://github.com/weltling/virtio-villain.git
-      VILLAIN_REF: v0.5.5
+      VILLAIN_REF: v0.6.4
     steps:
       - name: Code checkout
         uses: actions/checkout@v7
@@ -899,8 +899,7 @@ jobs:
             --vmm "${GITHUB_WORKSPACE}/target/release/cloud-hypervisor" \
             --blk-queues 2 --net-queues 2 --cpus 2 --memory 256M \
             --order=fast \
-            --exclude S0094 --exclude PCI0006 \
-            --jobs 4 --batch 10 --timeout 45 --log-dir villain-logs \
+            --jobs 4 --batch 10 --timeout 45 --retries 2 --log-dir villain-logs \
             --format junit --output villain-logs/results.xml \
             | tee villain-logs/run.out
       - name: Publish results to run summary