Add rss_hwm_reset binary

rss_hwm_reset is binary that reset RSS high-water mark counters for all
currently running processes. It runs in a separate process because it
needs dac_override capability.

The binary is invoked from a system service by flipping
sys.rss_hwm_reset.on property.

Bug: 119603799
Test: setprop sys.rss_hwm_reset.on 1
Change-Id: Ie853df3f11a3abb5faed9060a103770f11dd4848