RFR: 407: Clean up the swing initialization code

[Marcus Hirt]

Removing the workaround, since it isn't necessary anymore.

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

Commit messages:
 - 407: Clean up the swing initialization code

Changes: https://git.openjdk.org/jmc/pull/519/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=519&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-407
  Stats: 21 lines in 1 file changed: 0 ins; 21 del; 0 mod
  Patch: https://git.openjdk.org/jmc/pull/519.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/519/head:pull/519

PR: https://git.openjdk.org/jmc/pull/519