Fix building of OpenSearch 3.0.0-SNAPSHOT/main by installing JDK 21

Signed-off-by: Thomas Farr <tsfarr@amazon.com>

.github/actions/start-opensearch/action.yml

@@ -27,6 +27,7 @@ runs:
         if [[ "$RUNNER_OS" == "macOS" ]]; then
           brew install -q coreutils
         fi
+        unset JAVA_HOME
         OPENSEARCH_HOME=$(realpath ./opensearch-[1-9]*)
         CONFIG_DIR=$OPENSEARCH_HOME/config
         CONFIG_FILE=$CONFIG_DIR/opensearch.yml
@@ -48,7 +49,7 @@ runs:
             SECURITY_MINOR="${SECURITY_VERSION_COMPONENTS[1]}"
         
             if (( $SECURITY_MAJOR > 2 || ( $SECURITY_MAJOR == 2 && $SECURITY_MINOR >= 12 ) )); then
-              export OPENSEARCH_INITIAL_ADMIN_PASSWORD=$(LC_ALL=C tr -dc A-Za-z0-9 </dev/urandom | head -c 16)
+              export OPENSEARCH_INITIAL_ADMIN_PASSWORD="myStrongPassword123!"
             fi
         
             bash "$SECURITY_DIR/tools/install_demo_configuration.sh" -y -i -s

.github/workflows/integration-yaml-tests.yml

@@ -104,6 +104,12 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-nuget-
 
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: 'temurin'
+
       - name: Restore or Build OpenSearch
         id: opensearch_build
         uses: ./client/.github/actions/build-opensearch