[jdk16u] RFR: 8267345: VM crashes during dumping classlist with -Xshare:dump option

[Yumin Qi]

Hi, Please review
  The problem is caused by JDK-8247536: Support for pre-generated java.lang.invoke classes in CDS static archive
   Usually the dump with an appointed class list file, -XX:SharedClassListFile=<classlist>, the 'classlist' is collected by pre-run the application with -XX:DumpLoadedClassList, so it is rare case using -Xshare:dump and -XX:DumpLoadedClassList together, though we can do that.
   It is reproducible by run
   java -Xshare:dump -XX:DumpLoadedClassList=<any valid file name>
   The problem happened when regenerating lambda form invoker's holder classes, with which the re-generated class stream without a source associated (class is generated on fly).  Referencing to NULL source failed. Fix checks if source is valid.

Tests: tier1,tier2,tier3,tier4

Thanks
Yumin

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Commit messages:
 - 8267345: VM crashes during dumping classlist with -Xshare:dump option

Changes: https://git.openjdk.java.net/jdk16u/pull/119/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16u&pr=119&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267345
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk16u/pull/119.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16u pull/119/head:pull/119

PR: https://git.openjdk.java.net/jdk16u/pull/119