test_presence: Add debugging output to help track down a flake.
test_presence: Add debugging output to help track down a flake.

This test has been failing nondeterministically, and the debug output
should help us figure out why.

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