(ITS#8316) Broken cursor after mdb_cursor_del()

[h.b.furuseth@usit.uio.no]

Full_Name: Hallvard B Furuseth
Version: mdb.master, a98b74e6df6fdb9dbc29d44fe2879f96191d8904
OS: Linux x86_64
URL: ftp://ftp.openldap.org/incoming/Hallvard-Furuseth-151119.c
Submission from: (NULL) (2001:700:100:202::105)
Submitted by: hallvard


The test program does not find V(4) with the cursor which did
mdb_cursor_del().  It does find it with the unused cursor.

Broken by fca18d2586259c0e802d "ITS#7829 more for prev commit".