Remove an obsolete TODO.

Change-Id: Ie1b79eec88bf410548d42faca4f511387859e02d
diff --git a/vm/alloc/HeapSource.c b/vm/alloc/HeapSource.c
index 0891506..662f99d 100644
--- a/vm/alloc/HeapSource.c
+++ b/vm/alloc/HeapSource.c
@@ -721,9 +721,6 @@
     heap = hs2heap(hs);
 
     if (heap->bytesAllocated + n <= hs->softLimit) {
-// TODO: allocate large blocks (>64k?) as separate mmap regions so that
-//       they don't increase the high-water mark when they're freed.
-// TODO: zero out large objects using madvise
         ptr = mspace_calloc(heap->msp, 1, n);
         if (ptr != NULL) {
             countAllocation(heap, ptr, true);