-Run test suite with smaller aria keybuffer size (to make it possible to run more tests in parallel)
-Added test and extra code to ensure we don't leave keyread on for a handler table.
-Create on disk temporary files always with long data pointers if SQL_SMALL_RESULT is not used. This ensures that we can handle temporary files bigger than 4G.

mysql-test/include/default_mysqld.cnf:
  Run test suite with smaller aria keybuffer size
mysql-test/suite/maria/maria3.result:
  Run test suite with smaller aria keybuffer size
mysql-test/suite/sys_vars/r/aria_pagecache_buffer_size_basic.result:
  Run test suite with smaller aria keybuffer size
sql/handler.cc:
  Disable key read (extra safety if something went wrong)
sql/multi_range_read.cc:
  Ensure we have don't leave keyread on for secondary_file
sql/opt_range.cc:
  Simplify code with mark_columns_used_by_index_no_reset()
  Ensure that read_keys_and_merge() disableds keyread if it enables it
sql/opt_subselect.cc:
  Remove not anymore used argument for create_internal_tmp_table()
sql/sql_derived.cc:
  Remove not anymore used argument for create_internal_tmp_table()
sql/sql_select.cc:
  Use 'enable_keyread()' instead of calling HA_EXTRA_RESET. (Makes debugging easier)
  Create on disk temporary files always with long data pointers if SQL_SMALL_RESULT is not used. This ensures that we can handle temporary files bigger than 4G.
  Remove not anymore used argument for create_internal_tmp_table()
  More DBUG
sql/sql_select.h:
  Remove not anymore used argument for create_internal_tmp_table()