RFR: JDK-8289524: Add JFR JIT restart event [v2]

[Matthias Baesken]

> The JIT compiler restarts (see restart_compiler in NMethodSweeper::sweep_code_cache) would be a helpful addition to the JFR events. Currently we log the JIT stop operations in JFR (EventCodeCacheFull) but no restart.

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

  Incorporate JIT compiler restart into EventSweepCodeCache

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9334/files
  - new: https://git.openjdk.org/jdk/pull/9334/files/dbfb8775..29665ecb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9334&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9334&range=00-01

  Stats: 36 lines in 5 files changed: 10 ins; 22 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/9334.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9334/head:pull/9334

PR: https://git.openjdk.org/jdk/pull/9334