RFR: 8270290: NTLM authentication fails if HEAD request is used [v2]

[Alex Kasko]

> When HEAD request is used with a proxy (or a server) that requires NTLM, authentication fails when server returns large (8kb+) body along with NTLMSSP_CHALLENGE response.
> 
> Proposed fix is to check for ongoing NTLM auth in `reset()` and consume the response body in this case.
> 
> Alternatively the whole check for `HEAD` method in `reset()` can be dropped.

Alex Kasko has updated the pull request incrementally with one additional commit since the last revision:

  fix direct server and plain http proxy auth that became inadvertently broken

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4753/files
  - new: https://git.openjdk.java.net/jdk/pull/4753/files/c1c100d8..6027655d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4753&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4753&range=00-01

  Stats: 133 lines in 2 files changed: 75 ins; 32 del; 26 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4753.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4753/head:pull/4753

PR: https://git.openjdk.java.net/jdk/pull/4753