Docs tests: cat/health can have max_task_wait_time
Docs tests: cat/health can have max_task_wait_time

Make the doc test assertions ok with a non `-` value for
`max_task_wait_time`. These are rare, but possible:
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+multijob-unix-compatibility/os=oraclelinux/900/consoleFull

strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc,strapdata/elassandra5-rc