RFR: 8297976: Remove sun.net.ProgressMonitor and related classes [v2]

[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.

Daniel Jeliński has updated the pull request incrementally with one additional commit since the last revision:

  Add test

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11474/files
  - new: https://git.openjdk.org/jdk/pull/11474/files/e39aae11..e0e157c7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11474&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11474&range=00-01

  Stats: 293 lines in 1 file changed: 293 ins; 0 del; 0 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