RFR: 8308073: ClassLoaderExt::append_boot_classpath should handle dynamic archive

[Calvin Cheung]

Please review this simple fix for setting the `_has_platform_or_app_classes` flag for the dynamic archive case. The flag will be set to `false` in case the boot class path is appended via JVM TI.
Also adjusting two related JvmtiAddPath.java tests accordingly.

Passed tiers 1 - 4 testing.

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Commit messages:
 - 8308073: ClassLoaderExt::append_boot_classpath should handle dynamic archive

Changes: https://git.openjdk.org/jdk/pull/14127/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14127&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308073
  Stats: 12 lines in 3 files changed: 4 ins; 4 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/14127.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14127/head:pull/14127

PR: https://git.openjdk.org/jdk/pull/14127