RFR: 8361175: JFR: Document differences between method sample events

[Erik Gahlin]

Could I have a review that clarifies how the method sample events work?

- Added descriptions to NativeMethodSample, ExecutionSample and CPUTimeSample to clarify what they sample and what they don't sample.
- Removed the word "Method" from the labels of the CPUTimeSample and "ExecutionSample events for consistency and to avoid overly verbose event labels.
- Added the word "setting" so that the description of CPUTimeSample reads "throttle setting" instead of just "throttle".
- Changed the label for the CPUTimeSamplesLost event to "CPU Time Samples Lost", making it easier to associate with "CPU Time Sample" event. 
- Removed the percentage column from the "native-methods" view, as normalization doesn't make sense when mixing executing and waiting samples.


Testing: tets/jdk/jdk/jfr + tier1

Thanks
Erik

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Commit messages:
 - Initial

Changes: https://git.openjdk.org/jdk/pull/26132/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26132&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8361175
  Stats: 11 lines in 2 files changed: 2 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/26132.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26132/head:pull/26132

PR: https://git.openjdk.org/jdk/pull/26132