chore: migrate blocksuite test (#9222)

blocksuite/tests-legacy/utils/multiple-editor.ts

@@ -0,0 +1,15 @@
+import process from 'node:process';
+
+const editorIndex = {
+  0: 0,
+  1: 1,
+}[process.env.MULTIPLE_EDITOR_INDEX ?? ''];
+export const scope =
+  editorIndex == null
+    ? undefined
+    : editorIndex === 0
+      ? 'FIRST | '
+      : 'SECOND | ';
+export const multiEditor = scope != null;
+
+export const currentEditorIndex = editorIndex ?? 0;