RFR: 8220484: JFXPanel renders a slanted image with a hidpi monitor scale of 125% or 175%

[Oliver Schmidtmer]

In edge cases where monitor scaling of 1.25 or 1.75 is active, Math.ceil and Math.round produce different results and
EmbeddedScene#getPixels in JFXPanel#paintComponent causes an off-by-one error on the line width and therefore sheared
rendering.

The changes were already proposed by the submitter in JBS-8220484.

OCA is signed and send.

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Commit messages:
 - 8220484: calculate buffer size of JFXPanel#createResizePixelBuffer as EmbeddedScene#getPixels does

Changes: https://git.openjdk.java.net/jfx/pull/246/files
 Webrev: https://webrevs.openjdk.java.net/jfx/246/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8220484
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jfx/pull/246.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/246/head:pull/246

PR: https://git.openjdk.java.net/jfx/pull/246