RFR: 8276769: -Xshare:auto should tolerate problems in the CDS archive

[Yumin Qi]

Hi, Please review

  -Xshare:auto, which is the default, is supposed to use the specified archive if possible, but otherwise the VM should continue normal execution and ignore the specified archive(s). But current code in some case will fail and exit. Fixed to allow vm continue without abnormal exit, fixed related tests and added new tests to check various scenarios.

  Tests: tier1-4

Thanks
Yumin

-------------

Commit messages:
 - 8276769: -Xshare:auto should tolerate problems in the CDS archive

Changes: https://git.openjdk.java.net/jdk/pull/6731/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6731&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276769
  Stats: 317 lines in 7 files changed: 182 ins; 58 del; 77 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6731.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6731/head:pull/6731

PR: https://git.openjdk.java.net/jdk/pull/6731