Support printing import("a") (#458)

src/printer.js

@@ -458,6 +458,10 @@ function genericPrintNoParens(path, options, print) {
       parts.push(path.call(print, "source"), ";");
 
       return concat(parts);
+
+    case "Import": {
+      return "import";
+    }
     case "BlockStatement": {
       var naked = path.call(
         function(bodyPath) {

tests/dynamic_import/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,8 @@
+exports[`test test.js 1`] = `
+"import(\"module.js\");
+import(\"module.js\").then((a) => a);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+import(\"module.js\");
+import(\"module.js\").then(a => a);
+"
+`;

tests/dynamic_import/jsfmt.spec.js

@@ -0,0 +1 @@
+run_spec(__dirname, {parser: 'babylon'});

tests/dynamic_import/test.js

@@ -0,0 +1,2 @@
+import("module.js");
+import("module.js").then((a) => a);