test262 metrics mismatches shouldn't be checked when there are filters

[andreubotella]

The test262 runner allows running a filtered subset of the tests, by passing paths after the eval command. However, after #367, running the eval command will always check that the results of the current run of tests match the current metrics, and if the set of tests is filtered, they will usually not match. If there are filters present, this matching shouldn't be done.

cc @eliassjogreen