debug: use false as the default value for allThreadsContinued

fixes #18195

src/vs/workbench/parts/debug/electron-browser/rawDebugSession.ts

@@ -79,7 +79,7 @@ export class RawDebugSession extends v8.V8Protocol implements debug.ISession {
 		super(id);
 		this.emittedStopped = false;
 		this.readyForBreakpoints = false;
-		this.allThreadsContinued = false;
+		this.allThreadsContinued = true;
 		this.sentPromises = [];
 
 		this._onDidInitialize = new Emitter<DebugProtocol.InitializedEvent>();