Revert "Support initializing ProcessState with custom binder window size."

This reverts commit d26d3de9.

Reason for revert: simplicity

My original approach to unifying libbinder/libhwbinder has proven
futile, so undoing some of the damage (this function shouldn't exist,
and some of the reasons for having it in libhwbinder don't apply
anymore either).

Test: TH

Change-Id: I205f0e1818b6837f44f1a2d5d1a40133299f0d9a