test: switch to object spread in common/benchmark.js

PR-URL: #30309 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Trivikram Kamat <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Сковорода Никита Андреевич <[email protected]> Reviewed-By: Jiawen Geng <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: palmires

test/common/benchmark.js

@@ -18,7 +18,7 @@ function runBenchmark(name, args, env){
 
 argv.push(name);
 
-constmergedEnv=Object.assign({},process.env,env);
+constmergedEnv={ ...process.env,...env};
 
 constchild=fork(runjs,argv,{
 env: mergedEnv,