RFR: 8286962: java/net/httpclient/ServerCloseTest.java failed once with ConnectException [v2]

[Conor Cleary]

> **Issue**
> A failure in this test was observed whereby an unexpected connection from a client that was not created by the test caused the test to unsucessfully complete. 
> 
> **Solution**
> When a connection is accepted by the ServerSocket, some verification of the Request URI and of the Request Path is conducted. If the client connection is found to be invalid or external to the test, the connection is closed. The ServerSocket will continue to accept new connections until the correct parameters are met. Once a valid connection is accepted, the test behaves exactly as it previously did.

Conor Cleary has updated the pull request incrementally with one additional commit since the last revision:

  8286962: Validate method & path before URI

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9155/files
  - new: https://git.openjdk.org/jdk/pull/9155/files/92f4493c..f0de213c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9155&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9155&range=00-01

  Stats: 84 lines in 1 file changed: 29 ins; 25 del; 30 mod
  Patch: https://git.openjdk.org/jdk/pull/9155.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9155/head:pull/9155

PR: https://git.openjdk.org/jdk/pull/9155