zjsunit/handlebars: Support auto-registering partials.
zjsunit/handlebars: Support auto-registering partials.

webpack with handlebars-loader already does this, so we only need to
fix up the tests.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulipchat.com>

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