SF: prefer >=60Hz for fractional frame rates

If a layer requests a fractional frame rate that the display doesn't
naively support, favor at least 60Hz.
This is done by explicitly checking for known frame rates.

This change is needed to avoid selecting refresh rates such as 30Hz for
29.97fps content as it leads to frame drops.

Test: SF unit tests
Bug: 290839444
Bug: 292068399
Change-Id: I3dce623dd02b115323cb84f96e855d9010494a81