RFR: 8319925: CSS.BackgroundImage incorrectly uses double-checked locking

[Prasanta Sadhukhan]

CSS.BackgroundImage.getImage uses double-checked locking but the loadedImage field isn't declared as volatile. Without the volatile modifier, double-checked locking implementation is broken.

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

Commit messages:
 - 8319925: CSS.BackgroundImage incorrectly uses double-checked locking

Changes: https://git.openjdk.org/jdk/pull/16917/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16917&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319925
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/16917.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16917/head:pull/16917

PR: https://git.openjdk.org/jdk/pull/16917