RFR: 8224922: Access JavaFileObject from Element(s) [v14]

[Joe Darcy]

> Initial review to get some comments on the shape of the API. Tests are needed of course, as well as some tuning of the spec to better describe differences in behavior when class files rather than source files are the backing file type.

Joe Darcy 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 37 additional commits since the last revision:

 - Reflow paragraphs.
 - Fix spec typo; update copyrights.
 - Merge branch 'JDK-8224922' of https://github.com/jddarcy/jdk into JDK-8224922
 - Merge pull request #5 from lahodaj/JDK-8224922-3
   
   Adding tests for unnamed module/package and automatic modules.
 - Using a specific class file as the source.
 - Adjusting to the specification requiring returning of the outtermost class' FileObject, adding tests for unnamed module/package and automatic modules.
 - Merge branch 'master' into JDK-8224922
 - Add spec for automatic modules.
 - Refine spec.
 - Add explicit spec coverage of auxillary types in package-info files.
 - ... and 27 more: https://git.openjdk.java.net/jdk/compare/c1dd8692...04e8ea4b

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5038/files
  - new: https://git.openjdk.java.net/jdk/pull/5038/files/be167698..04e8ea4b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5038&range=13
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5038&range=12-13

  Stats: 2800 lines in 110 files changed: 2021 ins; 441 del; 338 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5038.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5038/head:pull/5038

PR: https://git.openjdk.java.net/jdk/pull/5038