test: log before and after RSS in memory leak test

Refs: nodejs#21076

PR-URL: nodejs#21080
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Anatoli Papirovski <[email protected]>
Reviewed-By: Сковорода Никита Андреевич <[email protected]>
Reviewed-By: Yuta Hiroto <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Tiancheng "Timothy" Gu <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

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

@@ -23,4 +23,4 @@ const after = process.memoryUsage().rss;
 
 // RSS should stay the same, ceteris paribus, but allow for
 // some slop because V8 mallocs memory during execution.
-assert(after - before < 5 << 20);
+assert(after - before < 5 << 20, `before=${before} after=${after}`);