Re: amcheck: support for GiST

The following review has been posted through the commitfest application:
make installcheck-world:  not tested
Implements feature:       not tested
Spec compliant:           not tested
Documentation:            not tested

Hi,
Together with Sergey we did a review and found a few things that need fixing:

- `contrib/amcheck/amcheck--1.5--1.6.sql:14` - missing space after comma
- `verify_gist.c` should be the second entry in meson.build, not at the end
- Some function arguments like `(GistCheckState * check_state, GistScanItem * stack)` have extra spaces after the `*` - should be `(GistCheckState *check_state, GistScanItem *stack)`
- Missing `#include "access/itup.h"` in `verify_common.h`
- Missing test file `007verify_gist_.pl` (not sure if should be created)
- `contrib/amcheck/sql/check_gist.sql` - missing cleanup statement `DROP TABLE toast_bug;`

Let us know if you need any clarification on these points!

- Miłosz and Sergey