pgsql: Fix amcheck for page checks concurrent to replay of btree page d
Fix amcheck for page checks concurrent to replay of btree page deletion
amcheck expects at least hikey to always exist on leaf page even if it is
deleted page. But replica reinitializes page during replay of page deletion,
causing deleted page to have no items. Thus, replay of page deletion can
cause an error in concurrent amcheck run.
This commit relaxes amcheck expectation making it tolerate deleted page with