RFR: 8262504: Some CLHSDB command cannot know they run on remote debugger

[Yasumasa Suenaga]

`pmap` and `pstack` CLHSDB command do not work on remote debugger, we can see following error message:

hsdb> pmap
not yet implemented (debugger does not support CDebugger)!

However, SA has different message for this purpose:

https://github.com/openjdk/jdk/blob/03d888f463c0a6e3fee70ed8ad606fc0a3082636/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/tools/PMap.java#L74-L78

SA should show "remote configuration is not yet implemented" when it works on remote debugger.

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Commit messages:
 - 8262504: Some CLHSDB command cannot know they run on remote debugger

Changes: https://git.openjdk.java.net/jdk/pull/2766/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2766&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262504
  Stats: 43 lines in 5 files changed: 31 ins; 0 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2766.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2766/head:pull/2766

PR: https://git.openjdk.java.net/jdk/pull/2766