[jdk25u] RFR: 8369319: java/net/httpclient/CancelRequestTest.java fails intermittently

[Sean Coffey]

Hardening of the java/net/httpclient/CancelRequestTest.java test case as per recommendation from @dfuch

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Commit messages:
 - 8369319

Changes: https://git.openjdk.org/jdk25u/pull/303/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=303&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369319
  Stats: 7 lines in 1 file changed: 4 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk25u/pull/303.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/303/head:pull/303

PR: https://git.openjdk.org/jdk25u/pull/303