swift234

Heap: Checkpoint leaks/heap/vm_map support

Huge allocation leaks are detected correctly.
Tiny allocation leaks are problematic, both false positive and false negative.

For example:

leaks Report Version:  2.0
Process 73345: 4980 nodes malloced for 1677 KB
Process 73345: 1 leak for 1048576 total leaked bytes.
Leak: 0x10aed0000  size=1048576  zone: SwiftZone_0x10adc35d8

Swift SVN r18007