[jdk11u-dev] RFR: 8271287: jdk/jshell/CommandCompletionTest.java fails with "lists don't have the same size expected"

[Martin Doerr]

Clean backport of JDK-8271287.

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Commit messages:
 - Backport 71788c69dbae854331f3393044dab458c906045f

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/481/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=481&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271287
  Stats: 9 lines in 1 file changed: 8 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/481.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/481/head:pull/481

PR: https://git.openjdk.java.net/jdk11u-dev/pull/481