dsp/lossless: prevent signed int overflow in left shift ops

force unsigned when shifting by 24.

Change-Id: I453601f33fdf01c516ef66ad23399ae6cbe032b3
instrument memory allocation routines for debugging

Some tracing code is activated by PRINT_MEM_INFO flag.
For debugging only! (not thread-safe, and slow).

Change-Id: I282c623c960f97d474a35b600981b761ef89ace9
Merge "instrument memory allocation routines for debugging"
Merge "dsp/lossless: prevent signed int overflow in left shift ops"
Reduce number of memory allocations while decoding lossless.

This change reduces the number of calls to WebPSafeMalloc from 200 to
100. The overall memory consumption is down 3% for Lenna image.

Change-Id: I1b351a1f61abf2634c035ef1ccb34050b7876bdd