[lworld] RFR: 8359370: [lworld] allow instance fields of identity classes to be readable in the prologue phase

[Vicente Romero]

Before this fix only strict fields were readable in the prologue phase. The proposed fix should allow any instance fields of identity classes to be readable in the prologue phase. This implies changes in flow analysis as before we were only tracking final and strict fields. There is also some "cooperation" needed in the code to detect cases when reading a field is not allowed in the prologue phase. For example some methods in Resolve don't have all the needed information at the moment they are dealing with some ASTs and part of the processing needs to be done in Attr

TIA

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Commit messages:
 - more changes
 - refactoring
 - test changes
 - minor fixes
 - restoring removed class files
 - additional changes
 - additional changes
 - Merge branch 'lworld' into JDK-8359370-v2
 - additional experiments
 - removing all checks from Resolve

Changes: https://git.openjdk.org/valhalla/pull/1523/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1523&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359370
  Stats: 375 lines in 23 files changed: 238 ins; 89 del; 48 mod
  Patch: https://git.openjdk.org/valhalla/pull/1523.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1523/head:pull/1523

PR: https://git.openjdk.org/valhalla/pull/1523