gitlab-ci: enable lint and run tools scripts in parallel

* splitting out the tools script allows less things to happen on the
  main job, and runs the tools script in parallel, which should speed
  things up.

* `gradle check` also runs lint, and anything else we might add to
  that meta-target.

* `gradle build` also runs tests, `gradle assemble` does not

.gitlab-ci.yml

@@ -5,19 +5,32 @@ cache:
     - .gradle/wrapper
     - .gradle/caches
 
-test:
+gradle:
   script:
     - export GRADLE_USER_HOME=$PWD/.gradle
-    - cd F-Droid
-    - ./tools/langs-list-check.py
-    - ./tools/check-string-format.py
-    - cd ..
-    - ./gradlew build
-    - ./gradlew checkstyle
-    - ./gradlew pmd
+    - ./gradlew assemble
+    # always report on lint errors to the build log
+    - sed -i -e 's,textReport .*,textReport true,' F-Droid/build.gradle
+    - ./gradlew check
     - echo no | android create avd --force -n fcl-test -t android-10 -b armeabi
     - emulator -force-32bit -avd fcl-test -no-skin -no-audio -no-window &
     - ./tools/wait-for-emulator
     - adb shell input keyevent 82
     - ADB_INSTALL_TIMEOUT=8 ./gradlew connectedCheck || { adb logcat -d '*:W'; exit 1; }
     - sed -n 's/.*"ctr2">\([0-9]*\)%<.*/Coverage - \1.0% covered\n/p' F-Droid/build/reports/coverage/debug/index.html
+
+pmd:
+  script:
+    - export GRADLE_USER_HOME=$PWD/.gradle
+    - ./gradlew pmd
+
+checkstyle:
+  script:
+    - export GRADLE_USER_HOME=$PWD/.gradle
+    - ./gradlew checkstyle
+
+tools:
+  script:
+    - cd F-Droid
+    - ./tools/langs-list-check.py
+    - ./tools/check-string-format.py