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 [v4]

[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.

Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:

  reflow URL::getHostAddress method description

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22153/files
  - new: https://git.openjdk.org/jdk/pull/22153/files/914a31f2..1580e419

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22153&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22153&range=02-03

  Stats: 3 lines in 1 file changed: 0 ins; 1 del; 2 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