[jdk15u-dev] RFR: 8273682: Upgrade Jline to 3.20.0

[Yuri Nesterenko]

Clean backport of JLine upgrade for parity with major releases. Tier1 and jline tests pass.

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Commit messages:
 - Backport b8cb76ad210cb3e7524c7f5b13cfe57746ac05d4

Changes: https://git.openjdk.java.net/jdk15u-dev/pull/197/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk15u-dev&pr=197&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273682
  Stats: 2667 lines in 47 files changed: 1830 ins; 473 del; 364 mod
  Patch: https://git.openjdk.java.net/jdk15u-dev/pull/197.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk15u-dev pull/197/head:pull/197

PR: https://git.openjdk.java.net/jdk15u-dev/pull/197