LibJS: Fix conditional expression precedence

This fixes the following from parsing incorrectly due to the comma
that occurs after the conditional:

  let o = {
    foo: true ? 1 : 2,
    bar: 'baz',
  };

Libraries/LibJS/Parser.cpp

@@ -1105,9 +1105,9 @@ NonnullRefPtr<ContinueStatement> Parser::parse_continue_statement()
 NonnullRefPtr<ConditionalExpression> Parser::parse_conditional_expression(NonnullRefPtr<Expression> test)
 {
     consume(TokenType::QuestionMark);
-    auto consequent = parse_expression(0);
+    auto consequent = parse_expression(2);
     consume(TokenType::Colon);
-    auto alternate = parse_expression(0);
+    auto alternate = parse_expression(2);
     return create_ast_node<ConditionalExpression>(move(test), move(consequent), move(alternate));
 }
 

Libraries/LibJS/Tests/object-basic.js

@@ -7,6 +7,7 @@ try {
         1: 23,
         foo,
         bar: "baz",
+        qux: true ? 10 : 20,
         "hello": "friends",
         [1 + 2]: 42,
         ["I am a " + computed + " key"]: foo,
@@ -17,6 +18,7 @@ try {
     assert(o["1"] === 23);
     assert(o.foo === "bar");
     assert(o["foo"] === "bar");
+    assert(o.qux === 10),
     assert(o.hello === "friends");
     assert(o["hello"] === "friends");
     assert(o[3] === 42);

Libraries/LibJS/Tests/ternary-basic.js

@@ -6,6 +6,8 @@ try {
     assert(x === 1 ? true : false);
     assert((x ? x : 0) === x);
     assert(1 < 2 ? (true) : (false));
+    assert((0 ? 1 : 1 ? 10 : 20) === 10);
+    assert((0 ? 1 ? 1 : 10 : 20) === 20);
 
     var o = {};
     o.f = true;