src: use NULL check macros to check nullptr

PR-URL: https://github.com/nodejs/node/pull/25916
Refs: https://github.com/nodejs/node/pull/20914
Reviewed-By: Masashi Hirano <shisama07@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

src/sharedarraybuffer_metadata.cc

@@ -75,7 +75,7 @@ SharedArrayBufferMetadata::ForSharedArrayBuffer(
     CHECK(source->IsExternal());
     SABLifetimePartner* partner =
         Unwrap<SABLifetimePartner>(lifetime_partner.As<Object>());
-    CHECK_NE(partner, nullptr);
+    CHECK_NOT_NULL(partner);
     return partner->reference;
   }