Fix alloc size in hqueue
We have allocate size($item) then cast the result to a pointer of that item.
This was discovered on macos with otp 25
```
Process 71176 stopped
* thread #16, name = '11_scheduler', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
frame #0: 0x00007ff81b74c363 libsystem_c.dylib`__chk_fail_overflow + 16
libsystem_c.dylib`:
-> 0x7ff81b74c363 <+16>: ud2
libsystem_c.dylib`:
0x7ff81b74c365 <+0>: pushq %rbp
0x7ff81b74c366 <+1>: movq %rsp, %rbp
0x7ff81b74c369 <+4>: leaq 0x7966(%rip), %rdi ; "detected source and destination buffer overlap"
Target 0: (beam.smp) stopped.
(lldb) bt
* thread #16, name = '11_scheduler', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
* frame #0: 0x00007ff81b74c363 libsystem_c.dylib`__chk_fail_overflow + 16
frame #1: 0x00007ff81b6dcf43 libsystem_c.dylib`__memset_chk + 18
frame #2: 0x0000000147d1969b hqueue.so`hqueue_nif_insert [inlined] hqueue_nif_node_alloc at hqueue_nif.c:117:5 [opt]
frame #3: 0x0000000147d1967a hqueue.so`hqueue_nif_insert(env=0x0000700008cb7d38, argc=3, argv=0x0000700008cb7e40) at hqueue_nif.c:296:18 [opt]
frame #4: 0x00000001000351f2 beam.smp`beam_jit_call_nif(c_p=0x0000000142e6cad8, I=<unavailable>, reg=0x0000700008cb7e40, fp=(hqueue.so`hqueue_nif_insert at hqueue_nif.c:269), NifMod=<unavailable>)(enif_environment_t*, int, unsigned long*), erl_module_nif*) at beam_jit_common.cpp:563:26 [opt]
frame #5: 0x000000014363856e
(lldb)
```
1 file changed
