chore: merge blocksuite source code (#9213)

blocksuite/framework/sync/src/utils/throw-if-aborted.ts

@@ -0,0 +1,9 @@
+// because AbortSignal.throwIfAborted is not available in abortcontroller-polyfill
+export function throwIfAborted(abort?: AbortSignal) {
+  if (abort?.aborted) {
+    throw new Error(abort.reason);
+  }
+  return true;
+}
+
+export const MANUALLY_STOP = 'manually-stop';