RFR: 8304911: Use OperatingSystem enum in some modules [v3]

[Roger Riggs]

> With the addition of `jdk.internal.util.OperatingSystem` references to the system property `os.name` can be replaced.
> This PR exports jdk.internal.util to:
>  - java.prefs,
>  - java.security.jgss,
>  - java.smartcardio,
>  - jdk.charsets,
>  - jdk.net,
>  - jdk.zipfs

Roger Riggs has updated the pull request incrementally with one additional commit since the last revision:

  Backout unneeded changes to module-info and default.policy.
  Fixup formatting.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13335/files
  - new: https://git.openjdk.org/jdk/pull/13335/files/aadf5bbd..5546b824

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13335&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13335&range=01-02

  Stats: 5 lines in 3 files changed: 1 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/13335.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13335/head:pull/13335

PR: https://git.openjdk.org/jdk/pull/13335