[jdk17u-dev] RFR: 8343855: HTTP/2 ConnectionWindowUpdateSender may miss some unprocessed DataFrames from closed streams

[Goetz Lindenmaier]

I backport this for parity with 17.0.17-oracle.
Also, it is a follow-up to JDK-8342075.

It needed resolves and adaptions:

**Resolved** the first chunk in Stream.java which adds the declaration of inputQLock.
The declaraions in the context have been modified by "8308310: HttpClient: Avoid logging or locking from within synchronized blocks".
Omitted one chunk fixing white space.
See first commit.

**Adaptions** can be found in the second commit.

The change uses locks from 8308310 and introduces a new lock.
To make this work further adaptions are needed (see extra commit):
I add edimports required by the new lock inputQLock.

stateLock is used by this change, but only introduced by 8308310.
Where 21 uses stateLock, the implementation in 17 locks
itself ("this").  I changed the use of stateLock introduced
by this change in pushDateaFrame() accordingly.

Actually, 17 declares a row of methods as synchronized
that are not handled by stateLock in 21, e.g. isCanceled().
So there is a difference in behavior wrt. this lock
between 17 and 21. 

I needed to fix two build issues in StreamFlowControlTest.java:

.../test/jdk/java/net/httpclient/http2/StreamFlowControlTest.java:299: error: incompatible types: try-with-resources not applicable to variable type
        try (var client = HttpClient.newBuilder().sslContext(sslContext).build()) {
                 ^
    (HttpClient cannot be converted to AutoCloseable)

/.../test/jdk/java/net/httpclient/http2/StreamFlowControlTest.java:300: error: cannot find symbol
            var request = HttpRequest.newBuilder(URI.create(h2Head)).HEAD().build();
                                                                    ^
  symbol:   method HEAD()
  location: interface Builder

The first I resolved similar to other places in this test in the backport that
brought the test to 17: https://github.com/openjdk/jdk17u-dev/pull/3786/commits/073bb3d5b0391cf9ad419a9b2be0d30afba1427b
Thanks to Aleksey for this detail.

For the second issue I replaced HEAD() by it's implementation.

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

Commit messages:
 - Backport bd6152f5967107d7b32db9bcfa224fc07314f098

Changes: https://git.openjdk.org/jdk17u-dev/pull/3852/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3852&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343855
  Stats: 187 lines in 5 files changed: 149 ins; 5 del; 33 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3852.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3852/head:pull/3852

PR: https://git.openjdk.org/jdk17u-dev/pull/3852