RFR: 8284686: Interval of < 1 ms disables ExecutionSample events [v6]

[Johannes Bechberger]

> Fixes the issue by rounding the period interval to the next full millisecond larger than zero.
> 
> The following from the bug report works now:
> 
> java -XX:StartFlightRecording=filename=flight.jfr,jdk.ExecutionSample#period=999us CLASS_FILE; jfr print --events jdk.ExecutionSample flight.jfr
> 
> It considers the period to be `1ms`, producing the recording as expected.

Johannes Bechberger has updated the pull request incrementally with two additional commits since the last revision:

 - Add TestShortPeriod
 - Remove TestPeriodSetting

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8183/files
  - new: https://git.openjdk.java.net/jdk/pull/8183/files/a9aebe04..e5b7f55c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8183&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8183&range=04-05

  Stats: 146 lines in 2 files changed: 95 ins; 51 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8183.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8183/head:pull/8183

PR: https://git.openjdk.java.net/jdk/pull/8183