RFR: 6946: There should be an option to build the agent in the build script [v21]

[Miroslav Wengner]

> https://bugs.openjdk.java.net/browse/JMC-6946
> added: 
> - build.sh --packageAgent
> - build.sh --runAgentExample

Miroslav Wengner has updated the pull request incrementally with two additional commits since the last revision:

 - 6946: missing letter
 - 6946: text improvements

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

Changes:
  - all: https://git.openjdk.java.net/jmc/pull/183/files
  - new: https://git.openjdk.java.net/jmc/pull/183/files/97c3951d..a4027714

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=183&range=20
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=183&range=19-20

  Stats: 7 lines in 2 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/jmc/pull/183.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/183/head:pull/183

PR: https://git.openjdk.java.net/jmc/pull/183