chore(spanner): accomodate experimental host in samples#12876

Adarsh-Shrivastava-001 wants to merge 2 commits intogoogleapis:maingoogleapis/google-cloud-java:mainfrom

Adarsh-Shrivastava-001:experimental_samplesAdarsh-Shrivastava-001/google-cloud-java:experimental_samplesCopy head branch name to clipboard