fix(runtime): handle expected exitCode rejection after terminating timed out test processes

ts/tstest.classes.runtime.node.ts

@@ -184,6 +184,8 @@ import '${absoluteTestFile.replace(/\\/g, '/')}';
         timeoutId = setTimeout(async () => {
           // Use tsrun's terminate() to gracefully kill the process
           await tsrunProcess.terminate();
+          // Swallow the expected rejection from the killed child process
+          tsrunProcess.exitCode.catch(() => {});
           reject(new Error(`Test file timed out after ${this.timeoutSeconds} seconds`));
         }, timeoutMs);
       });