RFR: JDK-8290845: Consider an alternative item separator for multi-item option values

[Jonathan Gibbons]

Please review a medium simple update to prefer the use of comma (`,`) instead of colon (`:`) in certain options taking a list of values.    Options taking a search path (like `--class-path`, `--source-path`, etc) are **not** affected.

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Commit messages:
 - JDK-8290845: Consider an alternative item separator for multi-item option values

Changes: https://git.openjdk.org/jdk/pull/11178/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11178&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290845
  Stats: 111 lines in 7 files changed: 57 ins; 19 del; 35 mod
  Patch: https://git.openjdk.org/jdk/pull/11178.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11178/head:pull/11178

PR: https://git.openjdk.org/jdk/pull/11178