[jdk17u] RFR: 8272903: Missing license header in ArenaAllocator.java [v2]

[Amit Kumar]

> Hi all,
> 
> This pull request contains a backport of commit [96614da0](https://github.com/openjdk/jdk/commit/96614da0254e7fd4ac9dd3c3059bf23c1aaf37ff) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by Maurizio Cimadamore on 9 Sep 2021 and was reviewed by Brian Burkhalter and Lance Andersen.
> 
> Thanks!

Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:

  updates copyright header year

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

Changes:
  - all: https://git.openjdk.org/jdk17u/pull/388/files
  - new: https://git.openjdk.org/jdk17u/pull/388/files/2cb1ec60..ed384965

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u&pr=388&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk17u&pr=388&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u/pull/388.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u.git pull/388/head:pull/388

PR: https://git.openjdk.org/jdk17u/pull/388