test_bugdown: Fix ignore-testcase feature for markdown_test_cases.
test_bugdown: Fix ignore-testcase feature for markdown_test_cases.

We accidentally were 'return'ing on encountering an ignored case, and thus
exiting the loop, not running further testcases.

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