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

[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.

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Commit messages:
 - Removing trailing whitespace.
 - 8341342: Elements.getAllModuleElements() does not work properly before JavacTask.analyze()

Changes: https://git.openjdk.org/jdk/pull/26694/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26694&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341342
  Stats: 73 lines in 2 files changed: 73 ins; 0 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