tests: Use check_tuple for realm filters.
tests: Use check_tuple for realm filters.

This also sets the stage to simplify
our check_list validator.

kou/zulip,synicalsyntax/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,timabbott/zulip,punchagan/zulip,andersk/zulip,rht/zulip,hackerkid/zulip,rht/zulip,eeshangarg/zulip,showell/zulip,hackerkid/zulip,zulip/zulip,showell/zulip,synicalsyntax/zulip,synicalsyntax/zulip,andersk/zulip,rht/zulip,zulip/zulip,rht/zulip,timabbott/zulip,punchagan/zulip,hackerkid/zulip,andersk/zulip,synicalsyntax/zulip,showell/zulip,showell/zulip,andersk/zulip,rht/zulip,brainwane/zulip,synicalsyntax/zulip,timabbott/zulip,brainwane/zulip,punchagan/zulip,andersk/zulip,kou/zulip,timabbott/zulip,showell/zulip,kou/zulip,punchagan/zulip,rht/zulip,timabbott/zulip,zulip/zulip,eeshangarg/zulip,synicalsyntax/zulip,eeshangarg/zulip,andersk/zulip,kou/zulip,kou/zulip,hackerkid/zulip,rht/zulip,brainwane/zulip,hackerkid/zulip,brainwane/zulip,eeshangarg/zulip,showell/zulip,punchagan/zulip,kou/zulip,hackerkid/zulip,punchagan/zulip,timabbott/zulip,brainwane/zulip,zulip/zulip,timabbott/zulip,showell/zulip,synicalsyntax/zulip,brainwane/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,brainwane/zulip,hackerkid/zulip,punchagan/zulip,andersk/zulip