fs: remove unnecessary ?? operator

This was introduced in 57678e5

With the `if` conditional around this statement, `options` will always
be evaluated as truthy. That means that the nullish coalescing operator
will always evaluate to the left side, make it unnecessary.

PR-URL: #43073
Reviewed-By: Zeyu "Alex" Yang <himself65@outlook.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: LiviaMedeiros <livia@cirno.name>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Akhil Marsonya <akhil.marsonya27@gmail.com>

lib/internal/fs/promises.js

@@ -476,7 +476,7 @@ async function read(handle, bufferOrParams, offset, length, position) {
       offset = 0,
       length = buffer.byteLength - offset,
       position = null
-    } = offset ?? ObjectCreate(null));
+    } = offset);
   }
 
   if (offset == null) {