Use `HttpResponse::connectionLabel` instead of `Http2TestExchange::connectionKey` to identify the connection request-response exchange is performed on, for the latter can accidentally return the same identifier again, e.g., if a closed connection is immediately reused.
------------- Commit messages: - Use `HttpResponse::connectionLabel` in `ConnectionFlowControlTest` Changes: https://git.openjdk.org/jdk/pull/28534/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28534&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8372147 Stats: 5 lines in 1 file changed: 0 ins; 1 del; 4 mod Patch: https://git.openjdk.org/jdk/pull/28534.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/28534/head:pull/28534 PR: https://git.openjdk.org/jdk/pull/28534
