[MachineOutliner] Sort by Benefit to Cost Ratio (#90264)

This PR depends on https://github.com/llvm/llvm-project/pull/90260

We changed the order in which functions are outlined in Machine
Outliner.

The formula for priority is found via a black-box Bayesian optimization
toolbox. Using this formula for sorting consistently reduces the
uncompressed size of large real-world mobile apps. We also ran a few
benchmarks using LLVM test suites, and showed that sorting by priority
consistently reduces the text segment size.

|run (CTMark/)   |baseline (1)|priority (2)|diff (1 -> 2)|
|----------------|------------|------------|-------------|
|lencod          |349624      |349264      |-0.1030%     |
|SPASS           |219672      |219480      |-0.0874%     |
|kc              |271956      |251200      |-7.6321%     |
|sqlite3         |223920      |223708      |-0.0947%     |
|7zip-benchmark  |405364      |402624      |-0.6759%     |
|bullet          |139820      |139500      |-0.2289%     |
|consumer-typeset|295684      |290196      |-1.8560%     |
|pairlocalalign  |72236       |72092       |-0.1993%     |
|tramp3d-v4      |189572      |189292      |-0.1477%     |

This is part of an enhanced version of machine outliner -- see
[RFC](https://discourse.llvm.org/t/rfc-enhanced-machine-outliner-part-1-fulllto-part-2-thinlto-nolto-to-come/78732).