test: fix flaky test-zlib-unused-weak.js

PR-URL: #38149 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

Author: oyyd

test/parallel/test-zlib-unused-weak.js

@@ -6,6 +6,7 @@ const zlib = require('zlib');
 
 // Tests that native zlib handles start out their life as weak handles.
 
+global.gc();
 constbefore=process.memoryUsage().external;
 for(leti=0;i<100;++i)
 zlib.createGzip();