Reduce reflect size

[molikto]

Objective

After #22452 is merged, the binary size increased a lot (and also compile time). Try to decrease binary size again.

Solution

Change the methods from generic to non-generic.

Testing

compile 3d_shapes example on macOS:

• before reflect PartialOrd #22452 : 94.5mb
• at reflect PartialOrd #22452 : 97.7mb
• at reflect PartialOrd #22452 + to dynamic (another attempt) : 94.9mb
• at reflect PartialOrd #22452 + dyn (this PR) : 94.5mb

also tried to see what if we disable reflection based cmp/eq entirely (which makes tests fails):

• disable reflection based cmp/eq entirely: 94.1mb

[MrGVSV]

Someone with more compiler knowledge will probably have more insight as to whether inline(never) is "correct" here (I would assume so as we don't really want these functions to be inlined).

But otherwise makes sense to me! I think whatever tradeoff in performance we have to make here is worth it to reduce binary size, since users can always register their actual implementations to avoid these functions from being called at all.