resourceloader: Move applyFilter() stats back to filter()

Follow-up b88e88b, which converted the count stats to include
timing information but incidentally moved the gathering point
inside the method, which meant it now also applied to uncached
minifications from logged-in user html views (called from one
branch higher in the filter method).

This should reset the 'resourceloader_cache.minify-js.miss.count'
back to normal levels.

Change-Id: I7761242f016e9026f5012352ec2f7297c1753f25