RFR: JDK-8365424 : [macos26] java/awt/Frame/DisposeTest.java fails on macOS 26

[Harshitha Onkar]

This test fails on macOS 26 due to slight color mismatch at background frame edges. A offset of 4 pixels is added as fix.

CI testing passes on other platforms.

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

Commit messages:
 - test fix for macOS26

Changes: https://git.openjdk.org/jdk/pull/27585/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27585&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365424
  Stats: 5 lines in 1 file changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/27585.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27585/head:pull/27585

PR: https://git.openjdk.org/jdk/pull/27585