test: use faster variant for rss in test-crypto-dh-leak

PR-URL: #36766
Refs: #34291
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-crypto-dh-leak.js

@@ -10,7 +10,7 @@ if (process.config.variables.asan)
 const assert = require('assert');
 const crypto = require('crypto');
 
-const before = process.memoryUsage().rss;
+const before = process.memoryUsage.rss();
 {
   const dh = crypto.createDiffieHellman(common.hasFipsCrypto ? 1024 : 256);
   const publicKey = dh.generateKeys();
@@ -21,7 +21,7 @@ const before = process.memoryUsage().rss;
   }
 }
 global.gc();
-const after = process.memoryUsage().rss;
+const after = process.memoryUsage.rss();
 
 // RSS should stay the same, ceteris paribus, but allow for
 // some slop because V8 mallocs memory during execution.