Refactor: Extract common code from LaunchRequestHandler's delegate

See ILaunchDelegate.java#L25-L27

    CompletableFuture<Response> launchInTerminal(LaunchArguments launchArguments, Response response, IDebugAdapterContext context);

    CompletableFuture<Response> launchInternally(LaunchArguments launchArguments, Response response, IDebugAdapterContext context);

There is common logic in implementation for both interfaces. The main differences in implementation for debug/noDebug are:

• launchInTerminal: It constructs different command string, and then take different actions according to response.
• launchInternally: It starts debuggee process in different ways.

Refactor work should be done to make code clean and readable.

まず ILaunchDelegate.java の25-27行目から始め、次に LaunchRequestHandler の delegate にある launchInTerminal と launchInternally の実装を調べます。共通ロジックと、issue で説明されている debug/noDebug の違いを比較します。共通の動作が統合され、これらの異なる起動動作を変更せずに delegate の可読性が保たれていれば完了です。