RFR: 8277459: Add jwebserver tool [v5]

[Julia Boes]

> This change introduces jwebserver, a dedicated JDK tool for the Simple Web Server. 
> 
> A description is provided in a follow-up comment.

Julia Boes has updated the pull request incrementally with one additional commit since the last revision:

  update comment about exit code

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6497/files
  - new: https://git.openjdk.java.net/jdk/pull/6497/files/dc1ac2dd..81499efa

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6497&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6497&range=03-04

  Stats: 6 lines in 2 files changed: 2 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6497.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6497/head:pull/6497

PR: https://git.openjdk.java.net/jdk/pull/6497