Re: tweak to a few index tests to hits ambuildempty() routine.

After analyzing this, I found out why we don't reach that Assert but we
have coverage shown - firstly, it reached via another test, vacuum;
secondly, it depends on the gcc optimization flag. We reach that Assert
only when using -O0.
If we build with -O2 or -Og that function is not reached (due to
different results of the heap_prune_satisfies_vacuum() check inside
heap_page_prune()).
But as the make checks mostly (including the buildfarm testing)
performed with -O2/-Og, it looks like that after 4fb5c794e5 we have
lost the coverage provided by the 4c51a2d1e4.

Amul Sul писал 2022-09-14 14:28:
> On Wed, Sep 14, 2022 at 12:16 PM <a(dot)kozhemyakin(at)postgrespro(dot)ru> wrote:
>>
>> I still wonder, if assert doesn't catch why that place is marked as
>> covered here?
>> https://coverage.postgresql.org/src/backend/access/gin/ginvacuum.c.gcov.html
>>
>
> Probably other tests cover that.
>
> Regards,
> Amul