RFR: 8293669: SA: Remove unnecssary "InstanceStackChunkKlass: InstanceStackChunkKlass" output when scanning heap

[Chris Plummer]

Get rid of the following "debugging" output that was introduced in the loom repo:

` InstanceStackChunkKlass: InstanceStackChunkKlass `

I'd like to push this as a trivial change.

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Commit messages:
 - Get rid of extra output

Changes: https://git.openjdk.org/jdk/pull/10245/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10245&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293669
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10245.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10245/head:pull/10245

PR: https://git.openjdk.org/jdk/pull/10245