Bound pending write events queue to avoid OOM

Bound the pending write events queue to a large amount of events in
total (100,000) so that we do not have out of memory crashes when the
sensors framework locks up. Events are 80B of memory each. So this
change caps are pending writes event queue to 8MB of memory.

Bug: 143302327
Test: atest android.hardware.sensors@2.0-halproxy-unit-tests &&
vts-tradefed run commandAndExit vts --skip-all-system-status-check
--primary-abi-only --skip-preconditions --module VtsHalSensorsV2_0Target

Change-Id: I5d0a7f382e3f61fbbe2c74b5c9cf13560432b84c