RFR: 8236842: Surprising 'multiple elements' behaviour from getTypeElement when cross-compiling with --release [v3]

[Jan Lahoda]

> Unqualified Elements.getTypeElement(CharSequence) and Elements.getPackageElement(CharSequence) search for elements
> across all modules in the module graph, and only return a value when they find exactly one element. This is
> troublesome, as an element (uniquely) visible from a root module may be "hidden" by an element that is not visible from
> any root module (i.e. is internal to some module that is not in the root module set). The idea proposed here is that
> these unqualified methods would first look for elements visible from the root modules, and would search the internals
> of other modules only if nothing would be found in the first round.  The draft of the corresponding CSR is here:
> https://bugs.openjdk.java.net/browse/JDK-8253168.

Jan Lahoda 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 four additional commits since
the last revision:

 - Linking to root and all modules definition.
 - Merge branch 'master' into JDK-8236842
 - Reflecting review comments - improving javadoc, avoid repeated search of modules that have already been searched.
 - 8253168: Surprising 'multiple elements' behaviour from getTypeElement when cross-compiling with --release

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/200/files
  - new: https://git.openjdk.java.net/jdk/pull/200/files/3eb2c0bd..33ca56ed

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=200&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=200&range=01-02

  Stats: 12332 lines in 424 files changed: 6792 ins; 4409 del; 1131 mod
  Patch: https://git.openjdk.java.net/jdk/pull/200.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/200/head:pull/200

PR: https://git.openjdk.java.net/jdk/pull/200