Inspected variable state is reset when the stack trace loads

Steps to reproduce:

- Pause at a breakpoint
- Quickly start expanding / collapsing variables tree
- When the stack trace loads, the variable tree state is reset

Demo:


Start by reproducing the issue in Flutter DevTools: pause at a breakpoint, expand or collapse the variables tree, and wait for the stack trace to load. Trace the debugger variable-tree state through the stack-trace loading path; done means the expanded and collapsed state remains unchanged after loading.

Scritto dal modello di indicizzazione a partire dal testo della issue.