RFR: 8297976: Remove sun.net.ProgressMonitor and related classes

[Daniel Jeliński]

Please review this patch that removes progress monitoring classes used by UrlConnection.
Since Java 9 these classes are not used in the JDK, and are not exported from java.base. If anyone was still using them, reimplementing them in user code should be pretty straightforward.

This PR also fixes the issue where MeteredStream finalizer could resurrect an unusable connection, causing unexpected exceptions in other parts of the code.

No new regression test; since we are removing the finalizer, I don't believe we will see the issue again. I can add a test for that if you think it still makes sense.

I had to adjust `ProxyModuleMapping.java` test which used `sun.net.ProgressListener` as an example of a module-private interface; I replaced it with another public interface from the same package.

Existing tier 1-3 tests continue to pass.

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Commit messages:
 - Update copyright
 - Update broken test
 - Remove broken MeteredStream finalizer
 - Remove progress monitoring classes

Changes: https://git.openjdk.org/jdk/pull/11474/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11474&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297976
  Stats: 895 lines in 13 files changed: 1 ins; 875 del; 19 mod
  Patch: https://git.openjdk.org/jdk/pull/11474.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11474/head:pull/11474

PR: https://git.openjdk.org/jdk/pull/11474