markdown_test_cases: Clean cases where bugdown_matches_marked is false.
markdown_test_cases: Clean cases where bugdown_matches_marked is false.

Fixes #7099.

dhcrzf/zulip,punchagan/zulip,tommyip/zulip,zulip/zulip,eeshangarg/zulip,jackrzhang/zulip,kou/zulip,andersk/zulip,zulip/zulip,shubhamdhama/zulip,shubhamdhama/zulip,rht/zulip,rishig/zulip,rht/zulip,zulip/zulip,jackrzhang/zulip,showell/zulip,tommyip/zulip,synicalsyntax/zulip,brainwane/zulip,eeshangarg/zulip,showell/zulip,zulip/zulip,punchagan/zulip,eeshangarg/zulip,timabbott/zulip,hackerkid/zulip,andersk/zulip,synicalsyntax/zulip,andersk/zulip,mahim97/zulip,andersk/zulip,rishig/zulip,rht/zulip,brainwane/zulip,eeshangarg/zulip,jackrzhang/zulip,hackerkid/zulip,jackrzhang/zulip,kou/zulip,timabbott/zulip,hackerkid/zulip,synicalsyntax/zulip,tommyip/zulip,showell/zulip,rishig/zulip,shubhamdhama/zulip,shubhamdhama/zulip,tommyip/zulip,eeshangarg/zulip,dhcrzf/zulip,jackrzhang/zulip,timabbott/zulip,dhcrzf/zulip,zulip/zulip,hackerkid/zulip,shubhamdhama/zulip,brainwane/zulip,zulip/zulip,dhcrzf/zulip,dhcrzf/zulip,synicalsyntax/zulip,showell/zulip,tommyip/zulip,zulip/zulip,timabbott/zulip,jackrzhang/zulip,kou/zulip,brainwane/zulip,tommyip/zulip,dhcrzf/zulip,hackerkid/zulip,eeshangarg/zulip,showell/zulip,hackerkid/zulip,kou/zulip,timabbott/zulip,punchagan/zulip,rht/zulip,dhcrzf/zulip,rht/zulip,punchagan/zulip,rishig/zulip,rht/zulip,eeshangarg/zulip,kou/zulip,mahim97/zulip,rishig/zulip,mahim97/zulip,shubhamdhama/zulip,showell/zulip,synicalsyntax/zulip,punchagan/zulip,showell/zulip,kou/zulip,synicalsyntax/zulip,timabbott/zulip,shubhamdhama/zulip,mahim97/zulip,jackrzhang/zulip,rht/zulip,rishig/zulip,mahim97/zulip,punchagan/zulip,brainwane/zulip,hackerkid/zulip,andersk/zulip,timabbott/zulip,andersk/zulip,mahim97/zulip,punchagan/zulip,tommyip/zulip,kou/zulip,synicalsyntax/zulip,rishig/zulip,brainwane/zulip,andersk/zulip,brainwane/zulip