RFR: 8359053: Implement JEP 504 - Remove the Applet API [v3]

[Phil Race]

> This is the implementation of JEP 504 - Remove the Applet API.
> API changes are
> - Remove the entire java.applet package
> - Remove the javax/swing/JApplet class
> - Remove applet related APIs in java.beans
> - Update javadoc referring to applets, including one gif image - now changed to an svg image
> - 
> Other changes are
> - Remove references to the removed classes
> - Remove obsolete tests
> - Update obsolete code comments
> 
> sun.awt.AppContext is even more obsolete now than it was before, but eliminating uses of that will be is not required,
> and will be follow-on internal clean up, at a later date, under unrelated bug ids, and likely not completed in the same
> release as this JEP is integrated.
> 
> I have extensively tested this - running all the automated tests used by CI tiers 1 to 8.

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8359053

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25698/files
  - new: https://git.openjdk.org/jdk/pull/25698/files/82f0ee55..a5b4ca5e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25698&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25698&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25698.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25698/head:pull/25698

PR: https://git.openjdk.org/jdk/pull/25698