RFR: JDK-8297007: IGV: Link/Unlink node selection of open tabs [v3]

[Tobias Holenstein]

> In IGV graphs can be opened in several tabs and then display them side-by-side. Previously, when the user selected nodes in tab A the selection was also applied in tab B. 
> 
> We now introduce a new global button to link and unlink the selection of different tabs.
> ![link_button](https://user-images.githubusercontent.com/71546117/201961318-e1263f6c-b3e9-41d5-a1f1-5493d5294bb5.png)
> 
> If the button is **pressed**, the selection is **linked** globally across tabs: 
> ![linked](https://user-images.githubusercontent.com/71546117/201960953-88f90c74-1c87-4c29-9881-47b55e7c26b9.png)
> 
> If the button is **not pressed**, the selection is **not linked** across tabs. This is the default setting:
> ![unlinked](https://user-images.githubusercontent.com/71546117/201961012-f531e7b9-1f23-4584-b207-02529ae25d5a.png)
> 
> # Implementation
> The `SelectionCoordinator` is responsible to update the other tabs when the selection changes. We simply disable the `SelectionCoordinator` when the link button is not pressed, and enable it otherwise.

Tobias Holenstein has updated the pull request incrementally with one additional commit since the last revision:

  Update src/utils/IdealGraphVisualizer/View/src/main/java/com/sun/hotspot/igv/view/DiagramViewModel.java
  
  whitespace
  
  Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11171/files
  - new: https://git.openjdk.org/jdk/pull/11171/files/4accab3e..5fa5878a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11171&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11171&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11171.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11171/head:pull/11171

PR: https://git.openjdk.org/jdk/pull/11171