RFR: 8071693: Introspector ignores default interface methods [v5]

[Archie L. Cobbs]

> The `Introspector` class was never updated to include `default` methods inherited from interfaces.
> 
> This patch attempts to fix that omission.

Archie L. Cobbs has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Add comment describing what IGNORABLE_INTERFACES is for.
 - Put braces around single-line "if" statement clauses in test.
 - Merge branch 'master' into JDK-8071693
 - Verify static method is not mistakenly identified as property getter.
 - Use Modifier.isAbstract() convenience method instead of bit masking test.
 - Put braces around single-line "if" statement clauses.
 - Use Set.of() to initialize IGNORABLE_INTERFACES set.
 - Include default methods inherited from interfaces in bean introspection.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13544/files
  - new: https://git.openjdk.org/jdk/pull/13544/files/106edcd6..ac90a10e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13544&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13544&range=03-04

  Stats: 2952 lines in 52 files changed: 2819 ins; 50 del; 83 mod
  Patch: https://git.openjdk.org/jdk/pull/13544.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13544/head:pull/13544

PR: https://git.openjdk.org/jdk/pull/13544