Evaluate single expression when running tests

This eliminates an extra "nil" value in the response.

plugin/fireplace.vim

@@ -1426,8 +1426,8 @@ augroup END
 " Section: Tests
 
 function! fireplace#capture_test_run(expr, ...) abort
-  let expr = '(require ''clojure.test) '
-        \ . '(try '
+  let expr = '(try'
+        \ . ' (require ''clojure.test)'
         \ . ' (binding [clojure.test/report (fn [m]'
         \ .  ' (case (:type m)'
         \ .    ' (:fail :error)'