chore(lru): use map.delete() directly

The default implementation already returns boolean if the object has been deleted.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete#return_value

internal/lrucache.js

@@ -17,12 +17,7 @@ class LRUCache {
  }
 
  delete (key) {
- if (this.map.has(key)) {
- this.map.delete(key)
- return true
- } else {
- return false
- }
+ return this.map.delete(key);
  }
 
  set (key, value) {