RFR: 8266900: java/net/httpclient/ShortResponseBody.java fails on windows with java.io.IOException: Unable to establish loopback connection

[Daniel Jeliński]

This PR reduces the number of requests performed by ShortResponseBody* tests from 570 to 100. It also reduces the number of httpclients created from one per request/URL to one per 10 requests. This in turn will translate to reduced frequency of failures caused by all ephemeral ports being in use.

Before this patch each test URL was repeated 12 times: 3 times with a dedicated client, then 3 more times with a client shared across all requests, repeated for sync and async.
After this patch each test URL is checked only 2 times, once with sync and once with async call.

The tests continue to pass.

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

Commit messages:
 - Reduce the number of test iterations

Changes: https://git.openjdk.org/jdk/pull/10794/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10794&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8266900
  Stats: 149 lines in 3 files changed: 9 ins; 57 del; 83 mod
  Patch: https://git.openjdk.org/jdk/pull/10794.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10794/head:pull/10794

PR: https://git.openjdk.org/jdk/pull/10794