RFR: 8272234: Pass originating elements from Filer to JavaFileManager [v2]

[Jan Lahoda]

> This is a first prototype of a patch that propagates originating elements from `Filer` (`createSourceFile`/`createClassFile`/`createResource`) to the corresponding methods in `JavaFileManager`. As file managers generally don't know about `Element`s, the `Element`s are first converted to their corresponding `FileObject`s (if any). As the currently existing methods only take one `FileObject` as a sibling of the newly created file, a new set of methods is proposed that take multiple originating files.
> 
> Any feedback on this prototype would be welcome.

Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:

 - Javadoc improvements.
 - Merge branch 'master' into ap-keep-originating-elements
 - Cleanup.
 - Improving testing
 - Updating @since
 - Merge branch 'master' into ap-keep-originating-elements
 - Another attempt to fix the test.
 - More attempts to fix the test.
 - Attempting to fix test.
 - Adding @since
 - ... and 6 more: https://git.openjdk.java.net/jdk/compare/4cb7124c...9396bbb4

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Changes: https://git.openjdk.java.net/jdk/pull/5076/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5076&range=01
  Stats: 579 lines in 7 files changed: 569 ins; 1 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5076.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5076/head:pull/5076

PR: https://git.openjdk.java.net/jdk/pull/5076