SF: Extract SurfaceFlinger::wouldPresentEarly

Short-circuit a few fetches and arithmetic operations.

Bug: 241285475
Test: libscheduler_test after Idf9f43b37f3479c94a478d154eaa46f43e0c6c9d
Change-Id: Ib40794cca0c44f8151ca9f37ba58ac4d892c66ee
2 files changed