[lworld] RFR: 8377162: [lworld] getResourceAsStream() doesn't work in preview mode for exploded images [v2]

[David Beaumont]

> Allow exploded module readers created for exploded system images to support preview mode.

David Beaumont 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 five additional commits since the last revision:

 - Merge branch 'lworld' into jdk_8377162_exploded_modules/squashed
 - revert unnecessary filter in ModulePatcher
 - Latest version
 - Limit awareness of preview resources to system modules only.
   
   * limit preview handling
   * Patch ModuleReaderTest from mainline
 - Preview mode for exploded system module readers
   
   * with better flag plumbing
   * Simpler approach with linked hash set
   * Revert weird import change
   * First cut at a preview aware module reader for exploded builds
   * Test for partiy of JRT file-system and class resources in preview mode

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/2032/files
  - new: https://git.openjdk.org/valhalla/pull/2032/files/6a79b0dc..7980c7de

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=2032&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=2032&range=00-01

  Stats: 4157 lines in 144 files changed: 1127 ins; 2533 del; 497 mod
  Patch: https://git.openjdk.org/valhalla/pull/2032.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2032/head:pull/2032

PR: https://git.openjdk.org/valhalla/pull/2032