The test CSSStyleDeclaration-has-indexed-property-getter is a frequent
source of merge conflicts between PRs that are adding to or otherwise
modifying the list of supported CSS properties.
This is primarily because the test prints out a numeric index of each
property along with the property. As far as I can tell the indexes are
inconsequential for what the test is trying to verify. So lets modify
the printout to only contain the properties without indexes.
