Optimize extractSetMethod(...) and findFunction(...)

[ZZZank]

• setter extracting is rewritten to do setter scanning in 1 pass instead of 2 passes
• a helper method failFastConversionWeights(...) that can compute conversion weights in batch
• computed weights from failFastConversionWeights(...) will now be cached to prevent computing weight again in preferSignature()

[ZZZank]

I've ran a test for these changes (https://github.com/ZZZank/rhino-mozilla/actions/runs/12994132974), seems to be working quite well

[gbrail]

This looks fine to me, although I don't consume this bit of Rhino functionality myself much anymore and it'd be nice to see if someone else could check it out.

Also, could you please run "./gradlew test testCodeCoverageReport" and take a look at the result (which is in tests/build/reports/jacoco/testCodeCoverageReport) for the parts that you changed?

I do see a big "we should never get here" in your code, and I won't worry as much about coverage there, but there are a few places where your new code checks for things and we never get there in the tests. It's not much but given how complex this code is I would feel better if you took at look at the coverage for the stuff you touched and see if you can cover as many of the edge cases as you can. Thanks!