RFR: 8267075: jcmd VM.cds should print directory of the output files

[Yumin Qi]

Hi, Please review the simple change for jcmd VM.cds to print directory of output file.
The printout will print out absolute file path, also a test scenario added.

Tests: tier1,tier2,tier3,tier4

Thanks
Yumin

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Commit messages:
 - 8267075: jcmd VM.cds should print directory of the output files

Changes: https://git.openjdk.java.net/jdk/pull/4576/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4576&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267075
  Stats: 35 lines in 3 files changed: 27 ins; 1 del; 7 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4576.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4576/head:pull/4576

PR: https://git.openjdk.java.net/jdk/pull/4576