RFR: 7046: Update to the 2021-03 platform [v2]

[Marcus Hirt]

> Also updating to latest babel for the platform versions that are available in 0.18.3.
> 
> Depending on if #234 gets in before or after this one, either this one will need to be updated to remove the chromium entry, or #234 will need to be updated to do it.
> 
> (Is it just me, or does JMC start really fast on 4.19? :) )

Marcus Hirt 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 three additional commits since the last revision:

 - Merge branch 'master' into 7046-update-2021-03
 - Removing chromium
 - 7046: Update to the 2021-03 platform

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

Changes:
  - all: https://git.openjdk.java.net/jmc/pull/235/files
  - new: https://git.openjdk.java.net/jmc/pull/235/files/7c2d7155..004195df

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=235&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=235&range=00-01

  Stats: 204 lines in 21 files changed: 111 ins; 37 del; 56 mod
  Patch: https://git.openjdk.java.net/jmc/pull/235.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/235/head:pull/235

PR: https://git.openjdk.java.net/jmc/pull/235