Fix try catch crasher bug due to null else case.

test/codegen/expect/try_catch.js

Index: test/codegen/expect/try_catch.js
diff --git a/test/codegen/expect/try_catch.js b/test/codegen/expect/try_catch.js
index 8a5d5b8c48a6597c9c2c36a9007c9c9f0c35eafd..167de1ef941b1b90f74beccfa814bdd3ddeaf793 100644
--- a/test/codegen/expect/try_catch.js
+++ b/test/codegen/expect/try_catch.js
@@ -27,13 +27,37 @@ var try_catch;
     }
 
   }
+  // Function baz: () → dynamic
+  function baz() {
+    try {
+      throw "finally only";
+    } finally {
+      return true;
+    }
+  }
+  // Function qux: () → dynamic
+  function qux() {
+    try {
+      throw "on only";
+    } catch (e) {
+      if (dart.is(e, core.String)) {
+        let t = dart.stackTrace(e);
+        throw e;
+      }
+    }
+
+  }
   // Function main: () → dynamic
   function main() {
     foo();
     bar();
+    baz();
+    qux();
   }
   // Exports:
   exports.foo = foo;
   exports.bar = bar;
+  exports.baz = baz;
+  exports.qux = qux;
   exports.main = main;
 })(try_catch || (try_catch = {}));