[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.

MICore/CommandFactories/gdb.cs、特に AllowCommandsWhileRunning() から始め、-gdb-set target-async on 周辺のセッション開始コマンドを追跡してください。-list-target-features の応答がどのように処理されるか、また実行中のコマンドの許可がどのように決定されるかを確認してください。対応している非同期ターゲットが認識され、プロセスが実行中であることだけを理由にコマンドが失敗しなくなれば完了です。