[code-reflection] RFR: Beef up reference resolution code and test

[Maurizio Cimadamore]

This PR improves the code for method/field/constructor resolution. To resolve fields and methods we have to perform two MH lookups, and find if any of them succeds. Since to code to do this is a bit convoluted, I have reimplemented the resolution support to use a more functional style (inspired by `Either` type).

I have also added several tests to make sure we test several lookup combinations, for instance/static method/fields, and also for super method resolution.

We will probably need more tests to cover the entire spectrum, but this should be at least a start.

I found 2 (!!) JDK issues when writing these tests, so some of the new tests contain workarounds.

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Commit messages:
 - Add resolution tests

Changes: https://git.openjdk.org/babylon/pull/682/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=682&range=00
  Stats: 676 lines in 6 files changed: 471 ins; 195 del; 10 mod
  Patch: https://git.openjdk.org/babylon/pull/682.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/682/head:pull/682

PR: https://git.openjdk.org/babylon/pull/682