SurfaceFlinger: use config groups

Composer 2.4 adds a new attribute for configs groups. This change
groups configs according to their group and store them in
RefreshRateConfigs.

Test: rev up composer to 2.4 and test refresh rate switching
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Test: adb shell /data/nativetest64/SurfaceFlinger_test/SurfaceFlinger_test
Bug: 141329414
Fixes: 139751853
Change-Id: Ic0bcd3da4bf6b73efa11a60c2594948ce030362f