Add FC_ORDER property into cache

"fontversion" used to be modified to sort out fonts as a technique.
But that lost the original purpose to do the version control between
releases.

This change adds the dedicated property into the cache.

Fixes fontconfig/fontconfig#226
3 jobs for issue/226 in 6 minutes and 18 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #2810827
mingw-build

00:05:02

passed #2810825
shared-build

00:06:18

passed #2810826
static-build

00:03:41