RFR: 8279366: CDS should allow alternative locations for JAR files in classpath

[Calvin Cheung]

Please review this RFE for allowing alternative locations for jar files in the app classpath during runtime.

During dump time, the longest common prefix of the app classpath will be stored in the CDS archive header. During runtime, existing checks of the app classpath will be performed first. Upon failure, the longest common prefix of the runtime app classpath will be computed and another check of the app classpath will be performed ignoring the longest common prefix.

Refer to the [bug report comment](https://bugs.openjdk.org/browse/JDK-8279366?focusedCommentId=14509536&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14509536) for an example.

Passed tiers 1 - 4 testing (including the new tests).

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Commit messages:
 - remove trailing whitespace
 - 8279366: CDS should allow alternative locations for JAR files in classpath

Changes: https://git.openjdk.org/jdk/pull/10615/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10615&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8279366
  Stats: 510 lines in 9 files changed: 492 ins; 0 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/10615.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10615/head:pull/10615

PR: https://git.openjdk.org/jdk/pull/10615