RFR: 8243009: SwingSet2 scrolling doesn't repaint properly on Catalina

[Ajit Ghaisas]

Issue : https://bugs.openjdk.java.net/browse/JDK-8243009

Root cause : If the same texture is provided as source and destination with some offset, copyArea function results in
texture tearing effect.

Fix : Copy the data from the source texture to a temporary buffer and then copy from that temporary buffer to the
destination (source texture with some offset)

Note : This solution may be slower, need to find an optimum way to copy data from MTLTexture to the same texture with
some offset.

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Commit messages:
 - fix for texture tearing on scroll

Changes: https://git.openjdk.java.net/lanai/pull/45/files
 Webrev: https://webrevs.openjdk.java.net/lanai/45/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8243009
  Stats: 24 lines in 1 file changed: 21 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/lanai/pull/45.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/45/head:pull/45

PR: https://git.openjdk.java.net/lanai/pull/45