RFR: 8281555: [macos] Get rid of deprecated Style Masks constants

[Dmitry Markov]

The Style Masks constants [1], which are utilised by AWT, were deprecated starting from macOS 10.12 Sierra. It is high time to replace them with new constants introduced by NSWindowStyleMask enumeration [2].

[1] - https://developer.apple.com/documentation/appkit/nspanel/style_masks
[2] - https://developer.apple.com/documentation/appkit/nswindowstylemask

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Commit messages:
 - 8281555: [macos] Get rid of deprecated Style Masks constants

Changes: https://git.openjdk.java.net/jdk/pull/7408/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7408&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281555
  Stats: 22 lines in 5 files changed: 0 ins; 0 del; 22 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7408.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7408/head:pull/7408

PR: https://git.openjdk.java.net/jdk/pull/7408