RFR: JDK-8297032: IGV: shortcut to center selected nodes

[Tobias Holenstein]

Introduce a new shortcut `CTRL-9`/ `CMD-9` to center the nodes that are currently selected in IGV

![center_selected_nodes](https://user-images.githubusercontent.com/71546117/201934216-0b65caa2-af62-4083-877b-e5747d5409ee.png)

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Commit messages:
 - JDK-8297032: IGV: shortcut to center selected nodes

Changes: https://git.openjdk.org/jdk/pull/11167/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11167&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297032
  Stats: 283 lines in 3 files changed: 281 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11167.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11167/head:pull/11167

PR: https://git.openjdk.org/jdk/pull/11167