test: upgrade graalvm to 25

Author: mpeddada1

.kokoro/build.sh

@@ -71,7 +71,18 @@ integration)
     ;;
 graalvm)
     # Run Unit and Integration Tests with Native Image
-    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative,native-tests,native-deps test -pl '!google-http-client-appengine'
+    echo "Install GraalVM 25"
+    echo "$JAVA_HOME"
+    pwd
+    mkdir -p ~/tools/jdk
+    cd ~/tools/jdk
+    wget https://download.oracle.com/graalvm/25/latest/graalvm-jdk-25_linux-x64_bin.tar.gz
+    tar -xf graalvm-jdk-25_linux-x64_bin.tar.gz
+    export JAVA_HOME=~/tools/jdk/graalvm-jdk-25+37.1
+    export PATH=$JAVA_HOME/bin:$PATH
+    java -version
+    echo "Running native image tests..."
+    cd "${scriptDir}/.."    mvn -B ${INTEGRATION_TEST_ARGS} -ntp -Pnative,native-tests,native-deps test -pl '!google-http-client-appengine'
     RETURN_CODE=$?
     ;;
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