Fix identifier size in the heap dump.

We're using addresses as IDs and previously we would have written
sizeof(void*) as the identifier size in the header. Heap references
are actually uint32_t so writting 4 bytes should be enough.

Bug: 16016862

(cherry picked from commit 3280517651195602253ed92a2749964e96cad27e)

Change-Id: I8b8a0f8d761314139ba01a8bc91c1a3db35b8ae9
1 file changed