RFR: 8360458: Rename Deferred<> to DeferredStatic<> and improve usage description

[Kim Barrett]

Please review this change that renames Deferred<> to DeferredStatic<>, to
better reflect the intended usage. (This involves renaming the source file.)
This change also revises the documentation comment for the class to better
describe the intended usage.

In addition, there are a number of cleanups:

(1) The include guard didn't get updated when the name was previously changed
to Deferred. It's updated here to reflect the new name.

(2) There were problems with the include block that are fixed here.

(3) The changes from JDK-8359923 are backed out. They aren't useful with the
intended usage model.

(4) A gtest is added to test the class's functionality.

Testing: mach5 tier1, including new gtest

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

Commit messages:
 - gtest for DeferredStatic
 - update uses
 - update
 - rename deferred.hpp => deferredStatic.hpp

Changes: https://git.openjdk.org/jdk/pull/25964/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25964&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360458
  Stats: 306 lines in 7 files changed: 210 ins; 91 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/25964.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25964/head:pull/25964

PR: https://git.openjdk.org/jdk/pull/25964