RFR: 8344221: Remove calls to SecurityManager and and doPrivileged in java.net.IDN, java.net.URL, java.net.URLConnection, sun.net.util.URLUtil, and java.net.URLStreamHandlerProvider after JEP 486 integration

[Daniel Fuchs]

Calls to getSecurityManager, checkPermission, and doPrivileged are removed.

- URLUtils.getConnectPermission is still used in the client area and couldn't be removed right away. [JDK-8344303](https://bugs.openjdk.org/browse/JDK-8344303) has been logged.

- Similarly, URLConnection.getPermission is a public API. [JDK-8344308](https://bugs.openjdk.org/browse/JDK-8344308) has been logged to deprecate it for removal.

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Commit messages:
 - 8344221: Remove calls to SecurityManager and and doPrivileged in java.net.IDN, java.net.URL, java.net.URLConnection, sun.net.util.URLUtil, and java.net.URLStreamHandlerProvider after JEP 486 integration

Changes: https://git.openjdk.org/jdk/pull/22153/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22153&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344221
  Stats: 123 lines in 5 files changed: 0 ins; 84 del; 39 mod
  Patch: https://git.openjdk.org/jdk/pull/22153.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22153/head:pull/22153

PR: https://git.openjdk.org/jdk/pull/22153