ARRNELEMS Out-of-bounds possible errors

Hi.

Per Coverity.

The commit ccff2d2
<https://github.com/postgres/postgres/commit/ccff2d20ed9622815df2a7deffce8a7b14830965>,
changed the behavior function ArrayGetNItems,
with the introduction of the function ArrayGetNItemsSafe.

Now ArrayGetNItems may return -1, according to the comment.
" instead of throwing an exception. -1 is returned after an error."

So the macro ARRNELEMS can fail entirely with -1 return,
resulting in codes failing to use without checking the function return.

Like (contrib/intarray/_int_gist.c):
{
int nel;

nel = ARRNELEMS(ent);
memcpy(ptr, ARRPTR(ent), nel * sizeof(int32));
}

Sources possibly affecteds:
contrib\cube\cube.c
contrib\intarray\_intbig_gist.c
contrib\intarray\_int_bool.c
contrib\intarray\_int_gin.c
contrib\intarray\_int_gist.c
contrib\intarray\_int_op.c
contrib\intarray\_int_tool.c:

Thoughts?

regards,
Ranier Vilela