Use KVM to run emulator tests on Linux (#312)

See https://github.blog/changelog/2023-02-23-hardware-accelerated-android-virtualization-on-actions-windows-and-linux-larger-hosted-runners/

.github/workflows/build.yaml

@@ -27,8 +27,14 @@ jobs:
       - run: ./gradlew build
 
   emulator:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     steps:
+      - name: Enable KVM
+        run: |
+          echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+          sudo udevadm control --reload-rules
+          sudo udevadm trigger --name-match=kvm
+
       - uses: actions/checkout@v4
       - uses: actions/[email protected]
         with: