RFR: 8344122: IGV: Extend c2 IdealGraphPrinter to send subgraphs to IGV [v6]

[Tobias Holenstein]

> IGV XML already support to define which graphs are visible when opened. Extend the IdealGraphPrinter::print... in C2 to define which nodes should be visible in IGV when sent over the network
> 
> ### Add a new option "!" to dump_bfs
> The option ! send the printed nodes of dump_bfs to IGV and shows them 
> 
> p find_node(0)->dump_bfs(1,0,"dcmxo+!")
> 
> dist dump
> ---------------------------------------------
>    1  51  Return  === 46 6 47 8 9 returns 39  [[ 0 ]] 
>    0   0  Root  === 0 51  [[ 0 1 3 26 ]] 
> Method printed over network stream to IGV
> 
> 
> <img width="668" alt="dump" src="https://github.com/user-attachments/assets/d476e8b0-c444-4cd3-b40d-4a8f35caba83">

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

  Update src/hotspot/share/opto/compile.cpp
  
  Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22076/files
  - new: https://git.openjdk.org/jdk/pull/22076/files/17765b07..7b9664ce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22076&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22076&range=04-05

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22076.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22076/head:pull/22076

PR: https://git.openjdk.org/jdk/pull/22076