transactional SELECT and ALTER TABLE ...  REBUILD PARTITION".

Remove unused code - TL_WRITE_ALLOW_READ thr_lock.c lock.






include/thr_lock.h:
  Remove TL_WRITE_ALLOW_READ.
mysys/CMakeLists.txt:
  Add thr_lock test to the list of CMake executables to build.
mysys/thr_lock.c:
  Remove TL_WRITE_ALLOW_READ thr_lock.c lock.
  Consequently, simplify lock compatibility rules.
  Remove unused code.
sql/sql_test.cc:
  Remove TL_WRITE_ALLOW_READ lock.