zjsunit: Restore necessary ternary conditions.
zjsunit: Restore necessary ternary conditions.

This reverts part of commit d4c681a937f527a39ef4202f2c26a98da96ded5c
(#20764).

The ternary conditions are necessary because __Rewire__ can be (and in
fact is) used to patch non-exported variables.

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

eeshangarg/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,rht/zulip,rht/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,andersk/zulip,rht/zulip,kou/zulip,rht/zulip,kou/zulip,kou/zulip,rht/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,zulip/zulip,rht/zulip,kou/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,zulip/zulip,zulip/zulip,andersk/zulip