RFR: JDK-8061729 : Update java/net tests to eliminate dependency on sun.net.www.MessageHeader and some other internal APIs [v4]

[Mahendra Chhipa]

> There are some regression tests depending on sun.net.www.MessageHeader, the internal API dependency should be removed. Some of other internal API dependancies are removed in following issues :
> JDK-8273142
> JDK-8268464
> JDK-8268133

Mahendra Chhipa has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into JDK-8061729
 - Implemented the review comments.
 - Implemented review comments.
 - JDK-8061729 : Update java/net tests to eliminate dependency on sun.net.www.MessageHeader and some other internal APIs

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5937/files
  - new: https://git.openjdk.java.net/jdk/pull/5937/files/b1b76be9..6f4b7d3a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5937&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5937&range=02-03

  Stats: 1041549 lines in 4815 files changed: 560242 ins; 453231 del; 28076 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5937.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5937/head:pull/5937

PR: https://git.openjdk.java.net/jdk/pull/5937