Rename BindingTable to ShmemIndex.

src/backend/storage/buffer/buf_init.c

src/backend/storage/ipc/ipci.c

src/backend/storage/ipc/shmem.c

src/backend/storage/ipc/spin.c

src/backend/storage/lmgr/lock.c

src/backend/storage/lmgr/proc.c

src/include/storage/ipc.h

src/include/storage/shmem.h