RFR: 8292738 : JInternalFrame backgroundShadowBorder & foregroundShadowBorder line is longer in Mac Look and Feel

[lawrence . andrews]

Border line is seen outside  round Rectangle both for JInternalFrame 
backgroundShadowBorder & foregroundShadowBorder line in mac L&F.
![Screen Shot 2022-08-22 at 4 17 49 
PM](https://user-images.githubusercontent.com/87324768/186021010-d21aed21-9e05-4b28-846b-2628e367f183.png)

I have circled the extra part of the line. To make it more visible I changed 
the color of the backgroundShadowBorder to red
![Screen Shot 2022-08-22 at 4 17 37 
PM](https://user-images.githubusercontent.com/87324768/186021095-cbfffdba-d43a-47e7-a50b-551c59cb767b.png)

Fixed the extra length of the line 
![Fixed](https://user-images.githubusercontent.com/87324768/186021195-688c3613-fc50-41c3-8cad-94173385dfeb.png)

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Commit messages:
 - 8292738 : JInternalFrame backgroundShadowBorder & foregroundShadowBorder 
line is longer in Mac Look and Feel

Changes: https://git.openjdk.org/jdk/pull/9971/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9971&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292738
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9971.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9971/head:pull/9971

PR: https://git.openjdk.org/jdk/pull/9971