RFR: 8280682: Refactor AOT code source validation checks

[Calvin Cheung]

This changset refactors CDS class paths and module paths validation code into a new class `AOTCodeSource` and related class `AOTCodeSourceConfig`. Code has been moved from filemap.[c|h]pp, classLoader.[c|h]pp, and classLoaderExt.[c|h]pp to aotCodeSource.[c|h]pp. CDS dependencies have been removed from `classLoader.cpp`. More refactoring could be done, such as removing `classLoaderExt.cpp`, in a future RFE.

Passed tiers 1 - 5 testing.

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Commit messages:
 - trailing whitespace
 - cleanup and add comments
 - 8280682: Refactor AOT code source validation checks

Changes: https://git.openjdk.org/jdk/pull/23476/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23476&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8280682
  Stats: 3172 lines in 40 files changed: 1346 ins; 1647 del; 179 mod
  Patch: https://git.openjdk.org/jdk/pull/23476.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23476/head:pull/23476

PR: https://git.openjdk.org/jdk/pull/23476