Merging utf16le from MySQL-5.6

added:
  mysql-test/include/ctype_heap.inc
  mysql-test/include/ctype_strtoll10.inc
  mysql-test/r/ctype_utf16le.result
  mysql-test/t/ctype_utf16le.test
modified:
  cmake/character_sets.cmake
  include/m_ctype.h
  mysql-test/r/ctype_ucs.result
  mysql-test/r/ctype_utf16.result
  mysql-test/r/ctype_utf32.result
  mysql-test/suite/funcs_1/r/innodb_func_view.result
  mysql-test/suite/funcs_1/r/memory_func_view.result
  mysql-test/suite/funcs_1/r/myisam_func_view.result
  mysql-test/suite/sys_vars/r/character_set_client_basic.result
  mysql-test/suite/sys_vars/r/character_set_connection_basic.result
  mysql-test/suite/sys_vars/r/character_set_database_basic.result
  mysql-test/suite/sys_vars/r/character_set_filesystem_basic.result
  mysql-test/suite/sys_vars/r/character_set_results_basic.result
  mysql-test/t/ctype_ucs.test
  mysql-test/t/ctype_utf16.test
  mysql-test/t/ctype_utf32.test
  mysys/charset-def.c
  sql/item_func.cc
  sql/sys_vars.cc
  strings/ctype-latin1.c
  strings/ctype-ucs2.c
Fixing test failure in the previous commit (utf16le merge from MySQL-5.6).
Recording new correct results in
  mysql-test/r/func_encrypt_ucs2.result
MDEV-4207 Invalid code in fts_savepoint_release() in InnoDB
MDEV-4243 Warnings/errors while compiling with clang