build: Update golden integration tests scripts (#12210)

sdk-platform-java was recently migrated to google-cloud-java. This
caused the golden integration tests scripts to stop working. Updated the
scripts and README to fix the issue.

Author: blakeli0

sdk-platform-java/scripts/update_golden.sh

@@ -11,8 +11,8 @@ cd srcjar_unpacked
 UNPACK_DIR=$PWD
 unzip -q -c "../${RAW_SRCJAR}" temp-codegen.srcjar | jar x
 
-mkdir -p ${BUILD_WORKSPACE_DIRECTORY}/test/integration/goldens/${API_NAME}
-cd ${BUILD_WORKSPACE_DIRECTORY}/test/integration/goldens/${API_NAME}
+mkdir -p ${BUILD_WORKSPACE_DIRECTORY}/sdk-platform-java/test/integration/goldens/${API_NAME}
+cd ${BUILD_WORKSPACE_DIRECTORY}/sdk-platform-java/test/integration/goldens/${API_NAME}
 
 # clear out existing Java and JSON files.
 find . -name '*.java' -delete

sdk-platform-java/test/integration/goldens/README.md

@@ -12,7 +12,7 @@ files.
 If they are not identical, then the integration test will fail.
 
 ```sh
-bazelisk test //test/integration:redis
+bazelisk test //sdk-platform-java/test/integration:redis
 ```
 
 ## How To Update Goldens
@@ -24,7 +24,7 @@ in `redis` folder.
 ```sh
 # In repository's root directory
 mvn clean install -DskipTests
-bazelisk run //test/integration:update_redis
+bazelisk run //sdk-platform-java/test/integration:update_redis
 ```
 
 ## Adding new integration tests