CLJS-1400: doseq does not behave as expected

add test. fix `with-out-str` for bootstrapped

Author: swannodette

src/main/clojure/cljs/core.cljc

@@ -2560,7 +2560,7 @@
   on a fresh StringBuffer.  Returns the string created by any nested
   printing calls."
   [& body]
-  `(let [sb# (goog.string.StringBuffer.)]
+  `(let [sb# (js/goog.string.StringBuffer.)]
      (binding [cljs.core/*print-newline* true
                cljs.core/*print-fn* (fn [x#] (.append sb# x#))]
        ~@body)

src/test/self/self_host/test.cljs

@@ -93,7 +93,7 @@
 
 (deftest test-eval-str
   (async done
-    (let [l (latch 6 done)]
+    (let [l (latch 7 done)]
       (cljs/eval-str st "(+ 1 1)" nil
         {:eval node-eval}
         (fn [{:keys [error value]}]
@@ -146,7 +146,12 @@
          :def-emits-var true}
         (fn [{:keys [error value]}]
           (is (nil? error))
-          (is (== 2 js/cljs.user.foo))
+          (inc! l)))
+      (cljs/eval-str st "(with-out-str (doseq [x [1 2]] (println x)))" nil
+        {:eval node-eval
+         :context :expr}
+        (fn [{:keys [error value]}]
+          (is (= "1\n2\n" value))
           (inc! l))))))
 
 #_(deftest test-eval-str-with-require