Deadlock in org.eclipse.debug.internal.ui.views.console.ProcessConsole

## Steps to reproduce

Junit test runs in debug mode and produces huge output to console (console is configured to be 10000000 bytes or so). Eclipse becomes almost unresponsive (because of slow processing of added text in console somehow), I pressed red square button in console toolbar to kill JUnit process and get a deadlock.

[threaddump-1776445734880.txt](https://github.com/user-attachments/files/26835797/threaddump-1776445734880.txt)

## Tested under this environment:
* Windows 11
* Eclipse IDE/Platform version Build id: 20251204-0850