RFR: 8372348: Adjust some UL / JFR string deduplication output messages [v3]

[Matthias Baesken]

> There is some UL output in the string deduplication code that is not very clear and has room for improvement.
> The inspected strings number should be shown and the new unknown strings get a changed text.
> (also the new JFR strip dedup event  description is slightly adjusted)

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Adjust output

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28455/files
  - new: https://git.openjdk.org/jdk/pull/28455/files/ba0e3410..2eb2857a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28455&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28455&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28455.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28455/head:pull/28455

PR: https://git.openjdk.org/jdk/pull/28455