[ADT] Delegate to DenseMap::find_as (NFC) (#155974)

DenseMap::find is a special case of DenseMap::find_as with a
restriction on the key type.

Author: kazutakahirata

llvm/include/llvm/ADT/DenseMap.h

@@ -174,20 +174,8 @@ class DenseMapBase : public DebugEpochBase {
     return contains(Val) ? 1 : 0;
   }
 
-  iterator find(const_arg_type_t<KeyT> Val) {
-    if (BucketT *Bucket = doFind(Val))
-      return makeIterator(
-          Bucket, shouldReverseIterate<KeyT>() ? getBuckets() : getBucketsEnd(),
-          *this, true);
-    return end();
-  }
-  const_iterator find(const_arg_type_t<KeyT> Val) const {
-    if (const BucketT *Bucket = doFind(Val))
-      return makeConstIterator(
-          Bucket, shouldReverseIterate<KeyT>() ? getBuckets() : getBucketsEnd(),
-          *this, true);
-    return end();
-  }
+  iterator find(const_arg_type_t<KeyT> Val) { return find_as(Val); }
+  const_iterator find(const_arg_type_t<KeyT> Val) const { return find_as(Val); }
 
   /// Alternate version of find() which allows a different, and possibly
   /// less expensive, key type.