SurfaceFlinger: calculate expected present once

Calculate the expected present time in the beginning of the frame
and use the same value across the frame composition.

Bug: 137873466
Test: App transitions
Change-Id: I0b41c62796f6150702e8d50ec7d28838d3a5aa87
(cherry picked from commit 7c03ce6508a7887e732abe03dc2dd53e146c008e)
Merged-In: I0b41c62796f6150702e8d50ec7d28838d3a5aa87
2 files changed