RFR: 8349847: Support configuring individual lint categories as errors

[Archie Cobbs]

This PR refines the `-Werror` flag to support lint categories just like `-Xlint` does. So, for example `-Werror:all,-preview` would cause an error if any warning other than a `preview` warning occurred.

A few notes:
* Some warnings emitted by the compiler do not have a corresponding `Lint` category. As always, they cause an error if `-Werror` is given, but what if `-Werror:all` is given instead? The answer given here is yes, an error will occur.
* The `-Werror` works the same way as before, i.e., any warning results in an error. That means if `-Werror` is given `-Werror:foo` flags have no effect.
* Refactoring has been done to allow `-Xlint` and `-Werror` to utilize the same "parsing" logic. The existing `-Xlint` flag has a particular behavior when conflicting flags are combined (e.g., `-Xlint:all -Xlint:none -Xlint:foo -Xlint:-foo` equals `-Xlint:all`). This behavior is been preserved and Javadocumented.
* A few minor cleanups are included

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

Commit messages:
 - Add support for -Werror:key.

Changes: https://git.openjdk.org/jdk/pull/23622/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23622&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349847
  Stats: 269 lines in 15 files changed: 202 ins; 38 del; 29 mod
  Patch: https://git.openjdk.org/jdk/pull/23622.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23622/head:pull/23622

PR: https://git.openjdk.org/jdk/pull/23622