RFR: 6909: Upgrade to Eclipse 2020-09 [v7]

[Marcus Hirt]

> Adds the Eclipse 2020-09 platform, upgrades 2020-09 and 2020-06 to use the 2020-06 babel bundles, and sets 2020-09 to
> be the default.

Marcus Hirt has updated the pull request incrementally with two additional commits since the last revision:

 - Update for running the UI-tests
 - Fixing UI-tests

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

Changes:
  - all: https://git.openjdk.java.net/jmc/pull/111/files
  - new: https://git.openjdk.java.net/jmc/pull/111/files/07b4e10f..482e8e6d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=111&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=111&range=05-06

  Stats: 14 lines in 2 files changed: 1 ins; 6 del; 7 mod
  Patch: https://git.openjdk.java.net/jmc/pull/111.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/111/head:pull/111

PR: https://git.openjdk.java.net/jmc/pull/111