So far the the real constructor for rw_lock_t has been rw_lock_create()
and the corresponding destructor has been rw_lock_free().
Code should not call new or delete when creating rw_lock_t instances
but use malloc()/free or some generic mechanism to allocate the memory.
They should not be created on the stack either.

We have three cases where we create rw_lock_t instances in the data segment.
buf/buf0buf.cc:static rw_lock_t buf_chunk_map_latch;
dict/dict0dict.cc:rw_lock_t dict_operation_lock;
trx/trx0i_s.cc:rw_lock_t in trx_i_s_cache;

Original patch was provided by Sunny Bains.

RB: 9271
Reviewed-by: Jimmy <Yang&lt;jimmy.yang@oracle.com>