Add PerfHUD ES profiling capabilities

The eglGetSystemTimeNV extension can be used to enable profiling
in PerfHUD ES. When the delta of two calls to eglGetSystemTimeNV
equals 0, we now cancels display lists updates. This allows the
tool to redraw the same frame several times in a row to run its
analysis.

For better results profiling should only be attempted after
setting viewroot.profile_rendering to true using adb shell
setprop.

Change-Id: I02e3c237418004cff8d6cb0b9a37126efae44c90