benchmark q11 producing incorrect results

[andygrove]

Describe the bug
Query produces too many rows due to an aggregate producing the wrong result. Changing the schema to use Float64 instead of Decimal(12,5) fixes it.

To Reproduce
Once #4015 is merged, unignore verify_q11.

Expected behavior
A clear and concise description of what you expected to happen.

Additional context
Add any other context about the problem here.

[andygrove]

I think that the root cause is #4035