Add an integration test for packaging

Uses two pre-existing packages to run some simple queries on a javascript
database.

tests/multi-language-repo/.github/codeql/codeql-config-packaging.yml

@@ -0,0 +1,10 @@
+name: Pack testing in the CodeQL Action
+
+disable-default-queries: true
+packs:
+  javascript:
+    - dsp-testing/codeql-pack1@0.0.3
+    - dsp-testing/codeql-pack2 # latest
+paths-ignore:
+  - tests
+  - lib

tests/multi-language-repo/main.js

@@ -1,3 +1,12 @@
+if (true) {
+    console.log("Hello, World!");
+    console.log("Good-bye, World!");
+}
+
 if (true) {
     console.log("Hello, World!");
 }
+
+if (true) {
+    // empty
+}