libhwui: enable O3 when compiling for perf

This reduces ui jitter by a lot.

Jitter (averge):

Before | After
----------------
~300ms | ~200ms

Test: Observe jitter values on uibench
Change-Id: I0caa4d013f7eb183a88a061ae22e07c401b40eaa
Signed-off-by: Vaisakh Murali <mvaisakh@statixos.com>
Signed-off-by: Hưng Phan <phandinhhungvp2001@gmail.com>