Refactor GitHub actions presubmit config

Extract boilerplate to a helper, and also update Error Prone to
only test with JDK 15 on macos and windows to avoid a combinatorial
explosion of test configurations. Most platform-specific issues are
not specific to a particular JDK version.

PiperOrigin-RevId: 348547557

.github/workflows/ci.yml

@@ -8,8 +8,16 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-latest, macos-latest, windows-latest ]
-        java: [ 15, 11, 8 ]
+        os: [ ubuntu-latest ]
+        java: [ 16-ea, 15, 11, 8 ]
+        # Only test on macos and windows with a single recent JDK to avoid a
+        # combinatorial explosion of test configurations.
+        # Most OS-specific issues are not specific to a particular JDK version.
+        include:
+          - os: macos-latest
+            java: 15
+          - os: windows-latest
+            java: 15
     runs-on: ${{ matrix.os }}
     steps:
       - name: 'Check out repository'
@@ -32,31 +40,6 @@ jobs:
         shell: bash
         run: mvn test -B
 
-  early_access:
-    name: 'JDK Early-Access'
-    continue-on-error: true
-    runs-on: ubuntu-latest
-    steps:
-      - name: 'Check out repository'
-        uses: actions/checkout@v2
-      - name: 'Cache local Maven repository'
-        uses: actions/cache@v2
-        with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-maven-
-      - name: 'Set up JDK ${{ matrix.java }}'
-        uses: actions/setup-java@v1
-        with:
-          java-version: 16-ea
-      - name: 'Install'
-        shell: bash
-        run: mvn install -DskipTests=true -Dmaven.javadoc.skip=true -B -V
-      - name: 'Test'
-        shell: bash
-        run: mvn test -B
-
   publish_snapshot:
     name: 'Publish snapshot'
     needs: test