RFR: 7903508: JMH: Remove the Unicode dot prefix from secondary results

[Aleksey Shipilev]

JMH secondary results, especially from profilers, are prepended with the odd Unicode symbol. This gets inconvenient when accessing the results from Java APIs (you'd need to copy-paste that symbol), or with hand parsing, etc. And the profilers are not even using that prefix consistently! `perfnorm`, for example, does not use a prefix.

The original intent for that prefix was to sort out the profiler results after the actual benchmark results. But the reporters already separate primary and secondary results, so that trick is not even needed.

This unfortunately has an effect on tools that parse the secondary results: they would now need to drop the prefix from the secondary result name. This should be a one-time minor inconvenience during the JMH upgrade.

See before/after results in JMH Samples changes in this PR.

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Commit messages:
 - Fix the test and samples
 - Something works
 - Fix

Changes: https://git.openjdk.org/jmh/pull/115/files
 Webrev: https://webrevs.openjdk.org/?repo=jmh&pr=115&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903508
  Stats: 222 lines in 26 files changed: 1 ins; 31 del; 190 mod
  Patch: https://git.openjdk.org/jmh/pull/115.diff
  Fetch: git fetch https://git.openjdk.org/jmh.git pull/115/head:pull/115

PR: https://git.openjdk.org/jmh/pull/115