REPLACE ... SELECT would require INSERT privileges on certain tables
when SELECT really suffices. Require INSERT only on target table.


mysql-test/r/insert_select.result:
  Bug#20989: View '(null).(null)' references invalid table(s)... on SQL SECURITY INVOKER
  
  Show that REPLACE ... SELECT requires INSERT privileges only on target table.
  (revised test with more view-fu)
mysql-test/t/insert_select.test:
  Bug#20989: View '(null).(null)' references invalid table(s)... on SQL SECURITY INVOKER
  
  Show that REPLACE ... SELECT requires INSERT privileges only on target table.
  (revised test with more view-fu)
sql/sql_insert.cc:
  Bug#20989: View '(null).(null)' references invalid table(s)... on SQL SECURITY INVOKER
  
  require SELECT rather than INSERT privs on tables that constitute the views we'll read