gitlab-ci: put all the static tests into test job

gitlab-ci used to run all of our jobs in parallel, now it mostly seems
to run them sequentially.  So splitting up the various parts of the CI
suite into separate jobs mostly slows things down.  This combines the
static tests into one job (lint, pmd, checkstyle, tools) with the JVM
tests aka Robolectric.  That makes three jobs from the previous six.

.gitlab-ci.yml

@@ -10,10 +10,16 @@ before_script:
 
 test:
   script:
+    - cd app
+    - ./tools/langs-list-check.py
+    - ./tools/check-string-format.py
+    - cd ..
     - ./gradlew assemble -PdisablePreDex
     # always report on lint errors to the build log
     - sed -i -e 's,textReport .*,textReport true,' app/build.gradle
     - ./gradlew lint -PdisablePreDex
+    - ./gradlew pmd -PdisablePreDex
+    - ./gradlew checkstyle -PdisablePreDex
     - ./gradlew test -PdisablePreDex || {
           for log in app/build/reports/*ests/*/*ml; do
               echo "read $log here:";
@@ -64,24 +70,6 @@ connected24:
       done
     - exit $EXITVALUE
 
-pmd:
-  script:
-    - ./gradlew pmd -PdisablePreDex
-
-checkstyle:
-  script:
-    - ./gradlew checkstyle -PdisablePreDex
-
-tools:
-  before_script:
-    - echo "ignored, no gradle needed"
-  script:
-    - cd app
-    - ./tools/langs-list-check.py
-    - ./tools/check-string-format.py
-  after_script:
-    - echo "ignored, no gradle needed"
-
 after_script:
     # this file changes every time but should not be cached
     - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock