RFR: 8298205: Prefer Member Initialization Lists for JFR classes in os_perf.hpp [v3]

[Tyler Steele]

> Unless there is a reason that I am unaware of for initializing member variables in this way, I believe it is better to use init lists here instead.

Tyler Steele has updated the pull request incrementally with one additional commit since the last revision:

  Change copyright year

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11547/files
  - new: https://git.openjdk.org/jdk/pull/11547/files/8ced110d..82cbcae8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11547&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11547&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11547.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11547/head:pull/11547

PR: https://git.openjdk.org/jdk/pull/11547