Fix await ternary parenthesis (#740)

* Add missing case.

* Update tests.

src/fast-path.js

@@ -419,6 +419,7 @@ FPp.needsParens = function(assumeExpressionContext) {
         case "LogicalExpression":
         case "NewExpression":
         case "ExportDefaultDeclaration":
+        case "AwaitExpression":
           return true;
 
         case "CallExpression":

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

@@ -18,9 +18,19 @@ exports[`test conditional-expression.js 1`] = `
 "async function f() {
   const result = typeof fn === \'function\' ? await fn() : null;
 }
+
+(async function() {
+  console.log(
+    await (true ? Promise.resolve(\"A\") : Promise.resolve(\"B\"))
+  );
+})()
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 async function f() {
   const result = typeof fn === \"function\" ? await fn() : null;
 }
+
+(async function() {
+  console.log(await (true ? Promise.resolve(\"A\") : Promise.resolve(\"B\")));
+})();
 "
 `;

tests/async/conditional-expression.js

@@ -1,3 +1,9 @@
 async function f() {
   const result = typeof fn === 'function' ? await fn() : null;
 }
+
+(async function() {
+  console.log(
+    await (true ? Promise.resolve("A") : Promise.resolve("B"))
+  );
+})()