Build both debug and release variants of webkit integration test apk

Test: ./gradlew buildOnServer
Change-Id: I1cfd122f6d86efd0bd2587cfd1360d405064c473
diff --git a/webkit/integration-tests/testapp/build.gradle b/webkit/integration-tests/testapp/build.gradle
index 4e10fdf..d80b428 100644
--- a/webkit/integration-tests/testapp/build.gradle
+++ b/webkit/integration-tests/testapp/build.gradle
@@ -24,6 +24,12 @@
     implementation(project(":webkit"))
 }
 
+tasks.all { task ->
+    if ("assembleRelease" == task.name) {
+        rootProject.tasks.getByName("buildOnServer").dependsOn(task)
+    }
+}
+
 android {
     defaultConfig {
         minSdkVersion 19
@@ -35,9 +41,5 @@
         release {
             minifyEnabled true
         }
-
-        debug {
-            minifyEnabled true
-        }
     }
 }