RFR: 8305578: X11GraphicsDevice.pGetBounds() is slow in remote X11 sessions [v6]

[Maxim Kartashev]

> Getting bounds of a `GraphicsDevice` and insets of a screen are fairly frequent operations. When working over the network (remote X session), those can take several *seconds* to complete, introducing repeated freezes even when typing in an editor feels only slightly sluggish.
> 
> On the other hand, neither bounds nor insets change very often - if at all - during the lifetime of an application. So caching their values seems like a natural solution to the problem. The caches need to be reset only when there's a possibility of change in the screens configuration.
> 
> A similar patch has been living in [JetBrains Runtime](https://github.com/JetBrains/JetBrainsRuntime/) for well over a year.

Maxim Kartashev has updated the pull request incrementally with one additional commit since the last revision:

  Double-checked locking for insets and less synchronization for bounds

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13346/files
  - new: https://git.openjdk.org/jdk/pull/13346/files/1db1431c..a3d32570

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13346&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13346&range=04-05

  Stats: 25 lines in 2 files changed: 4 ins; 10 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/13346.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13346/head:pull/13346

PR: https://git.openjdk.org/jdk/pull/13346