Build integration tests during CI (and release) (#800)

Note that this won't actually run them.

Additionally, the *unit* tests are also built, impying that we're
building them twice (once during this step, and possibly again when
running the unit tests.)

.github/workflows/ci.yml

@@ -21,4 +21,5 @@ jobs:
       run: |
         npm ci
         npm run build
+        npm run build:tests
         npm test

.github/workflows/release.yml

@@ -53,6 +53,7 @@ jobs:
       run: |
         npm ci
         npm run build
+        npm run build:tests
 
     - name: Run unit tests
       run: npm test

package.json

@@ -10,6 +10,7 @@
   },
   "scripts": {
     "build": "gulp build",
+    "build:tests": "gulp compile_test",
     "prepare": "npm run build",
     "lint": "run-p lint:src lint:test",
     "test": "run-s lint test:unit",