RFR: 8177814: jdk/editpad is not in jdk TEST.groups

[Aleksey Shipilev]

@prrace notices this here: https://github.com/openjdk/jdk/pull/5544#issuecomment-925396869. And I think it is the already open issue that this patch is fixing. While the original patch added the test in `jdk_other`, Phil suggests it to be added to `jdk_desktop`.

Additional testing:
 - [x] `jdk_editpad` is passing

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Commit messages:
 - Fix

Changes: https://git.openjdk.java.net/jdk/pull/5648/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5648&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8177814
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5648.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5648/head:pull/5648

PR: https://git.openjdk.java.net/jdk/pull/5648