RFR: 8254309: appcds GCDuringDump.java failed - class must exist

[Yumin Qi]

Hi,  Please review
  When CDS at dump time initializes archived heap, some classes are loaded. If at this time system runs out of memory the class will not be loaded. This is what we saw in this bug. The fix checks if OOM happened, if so we print out log and exit gracefully not causing a crash. Added a test case for testing purpose when exception/OOM happens during this stage. Also check during preload classes when OOM happens, exit vm with proper message.

Thanks
Yumin

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Commit messages:
 - 8254309: appcds GCDuringDump.java failed - class must exist

Changes: https://git.openjdk.java.net/jdk/pull/948/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=948&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254309
  Stats: 166 lines in 8 files changed: 152 ins; 10 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/948.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/948/head:pull/948

PR: https://git.openjdk.java.net/jdk/pull/948