regression tests fail for different block sizes

In master, 4 tests fail due to plan changes with blocksize 32K. The
failures started creeping in around 9.0.

I don't see a clean way to make the plans consistent with 8K and 32K
pages, so I was about to write this off as "we don't care much".

Then I ran with block size 1KB, and I got what appears to be a genuine
failure related to range types and/or spgist. I'm still investigating
that, which will be a separate discussion, but the fact that different
block sizes can catch real errors makes me think we should properly
support them in the regression tests.

Any ideas how we can make the plans consistent enough when the blocksize
varies?

Regards,Jeff Davis