test: add github actions functional tests for posix sidecar option

Enough people are making use of sidecar that we need to add
a CI test to make sure we have some coverage with this mode.

This add a couple small functional test fixes found wtih
enabling sidecar tests as well.

.github/workflows/functional-sidecar.yml

@@ -0,0 +1,31 @@
+name: functional tests (sidecar)
+permissions: {}
+on: pull_request
+
+jobs:
+  build:
+    name: RunTests
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Checkout
+      uses: actions/checkout@v6
+
+    - name: Set up Go
+      uses: actions/setup-go@v6
+      with:
+        go-version: 'stable'
+      id: go
+
+    - name: Get Dependencies
+      run: |
+        go mod download
+
+    - name: Build and Run
+      run: |
+        make testbin
+        ./runtests.sh --sidecar
+
+    - name: Coverage Report
+      run: |
+        go tool covdata percent -i=/tmp/covdata