mispec: don't use %f

The additional reporting, while nice, prevents the use of mispec on
integer-only builds

lua_tests/mispec.lua

@@ -117,8 +117,8 @@ M.runNextPending = function()
         M.succeeded = M.total - M.failed
         local elapsedSeconds = (tmr.now() - M.startTime) / 1000 / 1000
         print(string.format(
-            '\n\nCompleted in %.2f seconds.\nSuccess rate is %.1f%% (%d failed out of %d).',
-            elapsedSeconds, 100 * M.succeeded / M.total, M.failed, M.total))
+            '\n\nCompleted in %d seconds; %d failed out of %d.',
+            elapsedSeconds, M.failed, M.total))
         M.pending = nil
         M.queuedEventuallyCount = nil
     end