Revert "tests: try to make a test case less possible to fail on slow machines."

This reverts commit e5d7fc9.

Author: agentzh

t/135-worker-id.t

@@ -54,7 +54,7 @@ GET /lua
         content_by_lua_block {
             local counters = ngx.shared.counters
             local ok, c
-            for i = 1, 200 do
+            for i = 1, 100 do
                 c = counters:get("c")
                 if c >= 4 then
                     ok = true