RFR: 8344708: Compiler Implementation of Module Import Declarations [v6]

[Jan Lahoda]

> This is a patch to finalize the module imports feature. Please see:
> https://bugs.openjdk.org/browse/JDK-8344700

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 12 additional commits since the last revision:

 - Adjusting ToolProviderTest to the updated persistence handling.
 - Merge branch 'master' into JDK-8344708
 - Reflecting review feedback: cleanup formatting in ModuleInfo.
 - Reflecting review feedback - avoiding hardcoded constants.
 - Fixing test.
 - Cleanup, fixing tests.
 - Adjusting JShell defaults.
 - Fixing tests.
 - Cleanup - updated specification will permit requires transitive java.base; for all classfile versions; java.se no longer participates in preview.
 - Cleanup.
 - ... and 2 more: https://git.openjdk.org/jdk/compare/124c1cf4...4c14c3b0

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23801/files
  - new: https://git.openjdk.org/jdk/pull/23801/files/029e0dd5..4c14c3b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23801&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23801&range=04-05

  Stats: 213792 lines in 4489 files changed: 97109 ins; 91547 del; 25136 mod
  Patch: https://git.openjdk.org/jdk/pull/23801.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23801/head:pull/23801

PR: https://git.openjdk.org/jdk/pull/23801