Make deadlineThreshold 0

We give 2ms threshold for the deadline and this seems to cause some
misclassifications where an app's fault was classified as SF scheduling.
We designed the threshold with the idea of tweaking, so try 0 threshold
and see if it works better.

Bug: 191238086
Test: libsurfaceflinger_unittest
Change-Id: I0ac3d9ce3f9ec90f6b3188009d9d09a69afd37b2