RFR: 8341342: Elements.getAllModuleElements() does not work properly before JavacTask.analyze() [v3]

[Jan Lahoda]

> When calling `Elements.getTypeElement(...)` or `Elements.getPackageElement(...)`, javac itself ensures that the enter phase is already done. That is, sadly, not done for `Elements.getAllModuleElements()`. This PR fixes that.
> 
> See:
> https://github.com/openjdk/jdk/pull/18934/files#r1767657515
> for a practical case.

Jan Lahoda has updated the pull request incrementally with one additional commit since the last revision:

  Removing unnecessary explicit module initialization.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26694/files
  - new: https://git.openjdk.org/jdk/pull/26694/files/8651514c..5462926c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26694&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26694&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26694.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26694/head:pull/26694

PR: https://git.openjdk.org/jdk/pull/26694