NoPreference frame rate category is no-op

Change NoPreference frame rate category to behave like a no-op.
When all layers are NoPreference votes, the current frame rate should be
used, instead of choosing Min.
This also allows idle timer to trigger.

Bug: 328084518
Test: atest libsurfaceflinger_unittest
Test: Manual sysui jank suit
Change-Id: Ibe25ab8427367c5b86a1eaf0ed43434b6d270691
2 files changed