Reuse HUseListNode<>s when replacing instruction or input.

Reuse HUseListNode<>s when replacing instruction or input.

Compiling the Nexus 5 boot image with the 64-bit dex2oat
on host this CL reduces the memory used for compiling the
most hungry method, BatteryStats.dumpLocked(), by ~5.6MiB:

Before:
  MEM: used: 44393040, allocated: 45361248, lost: 968208
  Number of arenas allocated: 319,
  Number of allocations: 815492, avg size: 54
  ...
  UseListNode    10308480
  ...
After:
  MEM: used: 38554536, allocated: 39463008, lost: 908472
  Number of arenas allocated: 274,
  Number of allocations: 572221, avg size: 67
  ...
  UseListNode     4469976
  ...

With 32-bit dex2oat, the UseListNode would be 2/3 of the
values for 64-bit dex2oat (both before and after).

Bug: 28173563
Bug: 27856014

(cherry picked from commit 3c19d3e029a9fcc123d2c6fd1e5e13867d2cfe1f)

Change-Id: Iddd42d7545e4f97a13da63590b33711a5bbdd43b