Install jdk 1.8 because it uses JDK 24 and fails build due to incompatibility with errorProne 2.31

Author: kannanjgithub

buildscripts/kokoro/macos.sh

@@ -21,6 +21,7 @@ export GRADLE_FLAGS="${GRADLE_FLAGS:-} --max-workers=2"
 trap spongify_logs EXIT
 
 export -n JAVA_HOME
+brew install --cask temurin@8
 export PATH="$(/usr/libexec/java_home -v"1.8.0")/bin:${DOWNLOAD_DIR}/cmake-${CMAKE_VERSION}-macos-universal/CMake.app/Contents/bin:${PATH}"
 
 "$GRPC_JAVA_DIR"/buildscripts/kokoro/unix.sh