RFR: JDK-8344058 : Remove doPrivileged calls from macos platform sources in the java.desktop module

[Harshitha Onkar]

Post JEP-486 (Permanently Disable the Security Manager) cleanup. 
Calls to java.security.AccessController.doPrivileged are obsolete thus removed in this PR.

This PR addresses removal of AccessController.doPrivileged() calls from macos-platform files in the java.desktop module.Any SM related imports that are no longer needed are removed.

This PR is limited to removing doPrivileged() calls and excludes any refactoring, reformatting, or other clean up that is out-of-scope for this fix.

PS: I have explicitly add comments to the changes where a more watchful review is required.

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Commit messages:
 - doPrivileged() calls removed

Changes: https://git.openjdk.org/jdk/pull/22159/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22159&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344058
  Stats: 328 lines in 24 files changed: 7 ins; 186 del; 135 mod
  Patch: https://git.openjdk.org/jdk/pull/22159.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22159/head:pull/22159

PR: https://git.openjdk.org/jdk/pull/22159