fix: [Bigtable] Existing value SESSION_TYPE_TEST = -1 is changed to SESSION_TYPE_TEST = 9999 in enum SessionType#9138

bshaffer merged 2 commits intomaingoogleapis/google-cloud-php:mainfrom

owl-bot-copy-Bigtablegoogleapis/google-cloud-php:owl-bot-copy-BigtableCopy head branch name to clipboard