git: openjdk/jdk11u-dev: 8268555: Update HttpClient tests that use ITestContext to jtreg 6+1

[Goetz Lindenmaier]

Changeset: 62851233
Author:    Goetz Lindenmaier <goetz at openjdk.org>
Date:      2021-10-04 19:31:33 +0000
URL:       https://git.openjdk.java.net/jdk11u-dev/commit/62851233d3a5bc17061f2630492e0bd38f805d30

8268555: Update HttpClient tests that use ITestContext to jtreg 6+1

Reviewed-by: mdoerr
Backport-of: da043e99b830fa4fcbfdbdbed182abc394ba6fb1

! test/jdk/java/net/httpclient/AbstractThrowingPublishers.java
! test/jdk/java/net/httpclient/AbstractThrowingPushPromises.java
! test/jdk/java/net/httpclient/AbstractThrowingSubscribers.java
! test/jdk/java/net/httpclient/ForbiddenHeadTest.java
! test/jdk/java/net/httpclient/ProxySelectorTest.java
! test/jdk/java/net/httpclient/Response204V2Test.java
! test/jdk/java/net/httpclient/ShortResponseBody.java