RFR: 8322657: CDS filemap fastdebug assert while loading Graal CE Polyglot in isolated classloader [v2]

[Calvin Cheung]

> Please review this small fix for skipping the non-existent `SharedClassPathEntry` in `FileMapInfo::get_module_shared_path_index`.
> Please refer to the bug report for more details.
> 
> Passed tiers 1 - 4 testing, including the new test.

Calvin Cheung 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 three additional commits since the last revision:

 - comment from Matias
 - Merge branch 'master' of github.com:openjdk/jdk into 8322657-filemap-assert
 - 8322657: CDS filemap fastdebug assert while loading Graal CE Polyglot in isolated classloader

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17275/files
  - new: https://git.openjdk.org/jdk/pull/17275/files/6cf9eaf9..be7a746c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17275&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17275&range=00-01

  Stats: 6112 lines in 496 files changed: 3373 ins; 1190 del; 1549 mod
  Patch: https://git.openjdk.org/jdk/pull/17275.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17275/head:pull/17275

PR: https://git.openjdk.org/jdk/pull/17275