Change DirectByteBuffer to avoid allocating a cleaner for normal case

Cleaners are currently buggy and end up never getting cleaned up,
this was causing all direct byte buffers to never get GCed. For this
case, we probably want to avoid a cleaner anyways since the destructor
free() is trivial.

Bug: 25994460

Change-Id: Ibf30113c7092dbf2af3c717a4b578c4281975dec
1 file changed