[Feature Request] Fully support target-async on

When the session starts it sends:

-gdb-set target-async on

This is intended to enable asynchronuos commands, see https://sourceware.org/gdb/onlinedocs/gdb/Asynchronous-and-non_002dstop-modes.html

Whether the debugger actually supports it can then be checked using -list-target-features which will respond with something like:

^done,target-features=["async"]

If "async" appears in the target-features list, the debugger supports asynchronuos commands.

However, it never asks to see the supported target-features and starting the debugger and trying to issue commands results in:

Unable to perform this action because the process is running.

Looking in MICore/CommandFactories/gdb.cs in AllowCommandsWhileRunning(), and from what I can see there, it just says false.

Inizia da MICore/CommandFactories/gdb.cs, in particolare da AllowCommandsWhileRunning(), e segui i comandi di avvio della sessione relativi a -gdb-set target-async on. Esamina come vengono gestite le risposte di -list-target-features e come vengono determinate le autorizzazioni dei comandi durante l’esecuzione. Il lavoro è completato quando le destinazioni asincrone supportate vengono riconosciute e i comandi non falliscono più solo perché il processo è in esecuzione.