SurfaceFlinger: override frame rate for applications that use setFrameRate

(Uploaded again with a fix for b/176299745)

When possible, override the frame rate of an app if it explicitly
set a preferred frame rate.

Test: atest FrameRateOverrideHostTest
Test: SF unit tests
Bug: 170502573
Change-Id: I84a5a99f439ec7a8a808a0b26c630d4344acca4f