RFR: 8295324: JavaFX: Blank pages when printing

[eduardsdv]

This fixes a race condition between application and 'Print Job Thread' threads when printing.

The race condition occurs when application thread calls `endJob()`, which in effect sets the `jobDone` flag to true,
and when the 'Print Job Thread' thread was in the `synchronized` block in `waitForNextPage()` at that time.
The 'Print Job Thread' thread checks `jobDone` flag after exiting the `synchronized` block and, if it is true, skips the last page.

In this fix, not only the `jobDone` is checked, but also that there is no other page to be printed.
It was also needed to introduce a new flag 'jobCanceled', to skip the page if the printing was canceled by 'cancelJob()'.

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Commit messages:
 - 8295324: Fix skipping of pages when printing
 - 8295324: Apply patch with junit from the issue

Changes: https://git.openjdk.org/jfx/pull/916/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=916&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295324
  Stats: 463 lines in 6 files changed: 444 ins; 0 del; 19 mod
  Patch: https://git.openjdk.org/jfx/pull/916.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/916/head:pull/916

PR: https://git.openjdk.org/jfx/pull/916