Flux acceptance tests can be very slow

This is anecdotal, but recently my experience was:
- I added 20 acceptance tests to a single file in the `flux` repo
- I extended each of these 20 tests in `influxdb` to run the original test and also verify a planner rule was applied
- when I ran these tests (originals + extensions) I noticed that the extended tests took around 16s each on my machine, contributing more than 5 minutes to the run time.

I have since scaled back the number of tests, but the steps to reproduce this would be:
- Add 20 acceptance tests to Flux
- Extend each of those tests in `influxdb` to check for a planner rule
- Observe slowness when running those tests in influxdb

Start by reproducing the described Flux acceptance tests and their influxdb extensions, then compare the runtime of original tests with versions that verify a planner rule. The issue names no files or tests, and completion would require identifying and addressing the source of the reported slowness while confirming the extended tests no longer add excessive runtime.

Written by the indexing model from the issue text.