RFR: 8372002: VarHandle for receiver's superclass instance fields fails describeConstable

[Chen Liang]

In project Babylon work when a VarHandle needs to be unreflected, @mcimadamore discovered that our current unreflection of instance field var handles cannot unreflect instance fields from superclasses, and throws an InternalError instead.

We can easily fix this by iterating the superclasses for fields.

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Commit messages:
 - 8372002: VarHandle for receiver's superclass instance fields fails describeConstable

Changes: https://git.openjdk.org/jdk/pull/28355/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28355&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8372002
  Stats: 53 lines in 4 files changed: 38 ins; 2 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/28355.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28355/head:pull/28355

PR: https://git.openjdk.org/jdk/pull/28355