RFR: 8281678: appcds/dynamicArchive/ArchiveConsistency.java fails after JDK-8279997

[Ioi Lam]

Please review this trivial change - the two new test cases added in JDK-8279997 do not work when the tests are executed with `jtreg -vmoptions:-Xshare:off`. This patch disable the two test cases under such condition to avoid causing CI failures

A proper fix will be done in https://bugs.openjdk.java.net/browse/JDK-8281715

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Commit messages:
 - 8281678: appcds/dynamicArchive/ArchiveConsistency.java fails after JDK-8279997

Changes: https://git.openjdk.java.net/jdk/pull/7457/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7457&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281678
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7457.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7457/head:pull/7457

PR: https://git.openjdk.java.net/jdk/pull/7457