RFR: 8236919: Refactor com.sun.tools.javac.main.CommandLine into a reusable module for other JDK tools [v3]

[Christian Stein]

> This PR copies the `CommandLine.java` file from module `jdk.compiler` (package `com.sun.tools.javac.main`) into the `jdk.internal.opt` module, creating a new package with name `jdk.internal.opt`. That new `jdk.internal.opt` package is then exported to the following modules:
> - `jdk.jartool`
> - `jdk.jlink`
> - `jdk.jpackage`
> 
> Now, `jar`, `jlink`, and `jpackage` use a shared `CommandLine` class. In a future commit (presumable for JDK 21)  the original `CommandLine.java` file in `jdk.compiler` can and will be replaced with this new one in `jdk.internal.opt`. Same goes for the `jdk.javadoc` module.
> 
> - [x] Keep `CommandLine.java` in `jdk.compiler` module for the time being due to "JDK N-1 rule".
> - [x] Keep `CommandLine.java` in `jdk.javadoc` module for the time being due to "JDK N-1 rule".
> - [x] Remove `CommandLine.java` from `jdk.jartool` module
> - [x] Remove `CommandLine.java` from `jdk.jlink` module
> - [x] Remove `CommandLine.java` from `jdk.jpackage` module
> - [x] Check for related but renamed(?) usages of `CommandLine.java` in other JDK tools: `jshell`, `jdeps`, `jfr`, ...

Christian Stein has updated the pull request incrementally with one additional commit since the last revision:

  Remove entire "scary warning" paragraph

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11272/files
  - new: https://git.openjdk.org/jdk/pull/11272/files/7854e14c..6d2de1ee

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11272&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11272&range=01-02

  Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11272.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11272/head:pull/11272

PR: https://git.openjdk.org/jdk/pull/11272