Fixes the following bugs:

- Bug #29560: InnoDB >= 5.0.30 hangs on adaptive hash rw-lock 'waiting for an X-lock'

  Fixed a race condition in the rw_lock where an os_event_reset()
  can overwrite an earlier os_event_set() triggering an indefinite
  wait.
  NOTE: This fix for windows is different from that for other platforms.
  NOTE2: This bug is introduced in the scalability fix to the
  sync0arr which was applied to 5.0 only. Therefore, it need not be
  applied to the 5.1 tree. If we decide to port the scalability fix
  to 5.1 then this fix should be ported as well.

- Bug #32125: Database crash due to ha_innodb.cc:3896: ulint convert_search_mode_to_innobase

  When unknown find_flag is encountered in convert_search_mode_to_innobase()
  do not call assert(0); instead queue a MySQL error using my_error() and
  return the error code PAGE_CUR_UNSUPP. Change the functions that call
  convert_search_mode_to_innobase() to handle that error code by "canceling"
  execution and returning appropriate error code further upstream.