GitHub Workflows: Use setup-java,setup-graalvm built-in cache

In 3 workflows use built-in cache support in setup-java and setup-graalvm
actions and remove the separate cache action step.

.github/workflows/graalvm.yml

@@ -21,12 +21,7 @@ jobs:
           java-version: ${{ matrix.java-version }}
           distribution: ${{ matrix.distribution }}
           github-token: ${{ secrets.GITHUB_TOKEN }}
-      - name: Cache Gradle packages
-        uses: actions/cache@v4
-        with:
-          path: ~/.gradle/caches
-          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
-          restore-keys: ${{ runner.os }}-gradle
+          cache: 'gradle'
       - name: Build with Gradle
         run: ./gradlew nativeCompile --scan --info --stacktrace
       - name: Upload jsonrpc tool as artifact

.github/workflows/gradle.yml

@@ -15,17 +15,12 @@ jobs:
     steps:
     - name: Git checkout
       uses: actions/checkout@v4
-    - name: Set up JDK
+    - name: Set up Java
       uses: actions/setup-java@v4
       with:
         distribution: ${{ matrix.distribution }}
         java-version: ${{ matrix.java }}
-    - name: Cache Gradle packages
-      uses: actions/cache@v4
-      with:
-        path: ~/.gradle/caches
-        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
-        restore-keys: ${{ runner.os }}-gradle
+        cache: 'gradle'
     - name: Build with Gradle
       run: ./gradlew buildCI installDist --scan --info --stacktrace
     - name: Generate SHA256SUMS (Linux)

.github/workflows/regtest.yml

@@ -16,17 +16,12 @@ jobs:
     - uses: actions/checkout@v4
     - name: Download Omni Core (Bitcoin Core superset)
       run: ./test-download-omnicore-ubuntu.sh
-    - name: Set up JDK
+    - name: Set up Java
       uses: actions/setup-java@v4
       with:
         distribution: ${{ matrix.distribution }}
         java-version: ${{ matrix.java }}
-    - name: Cache Gradle packages
-      uses: actions/cache@v4
-      with:
-        path: ~/.gradle/caches
-        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
-        restore-keys: ${{ runner.os }}-gradle
+        cache: 'gradle'
     - name: Run RegTests
       run: ./test-run-regtest.sh
     - name: Upload RegTest results as artifact