benchmark: remove v8ForceOptimization calls

This removes common.v8ForceOptimization calls from url and vm benchmark
files.

PR-URL: https://github.com/nodejs/node/pull/11908
Fixes: https://github.com/nodejs/node/issues/11895


Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>