CLJS-1589: Self-host: case fail with nil

In bootstrapped ClojureScript, case will fail with a nil test because
char? will throw. This revision nil-patches the char? test conditionallyfor bootstrapped mode.

Author: mfikes

src/main/clojure/cljs/core.cljc

@@ -2140,7 +2140,7 @@
              esym    (gensym)
              tests   (keys pairs)]
     (core/cond
-      (every? (some-fn core/number? core/string? core/char? #(const? env %)) tests)
+      (every? (some-fn core/number? core/string? #?(:clj core/char? :cljs (core/fnil core/char? :nonchar)) #(const? env %)) tests)
       (core/let [no-default (if (odd? (count clauses)) (butlast clauses) clauses)
                  tests      (mapv #(if (seq? %) (vec %) [%]) (take-nth 2 no-default))
                  thens      (vec (take-nth 2 (drop 1 no-default)))]

src/test/self/self_host/test.cljs

@@ -653,6 +653,16 @@
           (is (nil? error))
           (is (= :aliased.core/bar value)))))))
 
+(deftest test-CLJS-1589
+  (cljs/eval-str st
+    "(case 1 nil nil :x)"
+    nil
+    {:eval    node-eval
+     :context :expr}
+    (fn [{:keys [error value]}]
+      (is (nil? error))
+      (is (= :x value)))))
+
 #_(deftest test-eval-str-with-require
   (async done
     (let [l (latch 3 done)]