[code-reflection] RFR: Beef up reference resolution code and test [v2]

[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.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  recordify RecordTypeRef
  drop redundant instanceof

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Changes:
  - all: https://git.openjdk.org/babylon/pull/682/files
  - new: https://git.openjdk.org/babylon/pull/682/files/d2875683..d38a687a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=682&range=01
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=682&range=00-01

  Stats: 33 lines in 2 files changed: 0 ins; 29 del; 4 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