hosted: Shrink audiobuffer to (MEMORY_SIZE-1) megabytes
This represents a 256K increase from the former (MEMORYSIZE-0.75), and
is necessary due to the growth in our binary sizes over the past decade
or so.
It is debatable if this is enough given that our actual memory
usage is approximately (MEMORYSIZE+3) megabytes (plus runtime OS
overhead) for the typical hosted build, but giving the host OS a bit
more breathing room is warranted.
Change-Id: I53e044585a32efd50a85e68d64fd21921eda01a3