FRotator::SetClosestToMe(FRotator) Doesn't Set The Correct Value

FRotator::SetClosestToMe(FRotator) doesn't set the correct value.

Attached are files with the demonstrative code.

Found in 4.23.1 CL#9631420
Reproduced in 4.24 Preview 4 CL#10570792, 4.25 CL#10520629

1. Create a C++ project.
2. Create a class using the code in the attached files.
3. Place an instance of the class in a level and play the level.
4. Look at the output log.

Results: RotatorB's roll valuer is 180.

Expected: RotatorB roll valuer is 0.