Merge pull request #12606 from robin850/apps-with-spaces

Make the application name snake cased when it contains spaces
Fix order dependent tests
stop using `send` so that method privacy is respected and we get a small
perf increase
use the provided block to filter lists
do not search through the keys array twice
this should be private, no other instances of Root should call it
Make that check_schema_file works on paths with spaces