Fix extra parens for update expressions (#796)

* Remove parens around UpdateExpression when parent is CallExpression.

* Add new test case.

src/fast-path.js

@@ -258,7 +258,6 @@ FPp.needsParens = function(assumeExpressionContext) {
           return name === "object" && parent.object === node;
 
         case "TaggedTemplateExpression":
-        case "CallExpression":
         case "NewExpression":
           return true;
 

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

@@ -4,9 +4,11 @@ exports[`update_expression.js 1`] = `
 "(this.x++).toString()
 new (r++);
 (x++)();
+const uuid = String(this._uuidCounter++);
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 (this.x++).toString();
 new (r++)();
 (x++)();
+const uuid = String(this._uuidCounter++);
 "
 `;

tests/update_expression/update_expression.js

@@ -1,3 +1,4 @@
 (this.x++).toString()
 new (r++);
 (x++)();
+const uuid = String(this._uuidCounter++);