[async functions] Disallow 'await' in arrow params inside async functions

test/cctest/test-parsing.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7780 matching lines @@
   const char* body_data[] = {
     "var async = 1; return async;",
     "let async = 1; return async;",
     "const async = 1; return async;",
     "function async() {} return async();",
     "var async = async => async; return async();",
     "function foo() { var await = 1; return await; }",
     "function foo(await) { return await; }",
     "function* foo() { var await = 1; return await; }",
     "function* foo(await) { return await; }",
-    "var f = (await) => await;",
     "var f = () => { var await = 1; return await; }",
     "var O = { method() { var await = 1; return await; } };",
     "var O = { method(await) { return await; } };",
     "var O = { *method() { var await = 1; return await; } };",
     "var O = { *method(await) { return await; } };",
 
     "(function await() {})",
     NULL
   };
   // clang-format on
@@ skipping 66 matching lines @@
     "class C { static async prototype() {} }",
     "class C {}; class C2 extends C { static async prototype() {} }",
 
     "var f = async() => ((async(x = await 1) => x)();",
 
     "var asyncFn = async function() { function await() {} }",
     "var asyncFn = async() => { function await() {} }",
     "var O = { async method() { function await() {} } }",
     "async function foo() { function await() {} }",
 
+    "async function foo() { var f = (await) => await; }",
+
     // Henrique Ferreiro's bug (tm)
     "(async function foo1() { } foo2 => 1)",
     "(async function foo3() { } () => 1)",
     "(async function foo4() { } => 1)",
     "(async function() { } foo5 => 1)",
     "(async function() { } () => 1)",
     "(async function() { } => 1)",
     "(async.foo6 => 1)",
     "(async.foo7 foo8 => 1)",
     "(async.foo9 () => 1)",
@@ skipping 289 matching lines @@
     "(a,);",
     "(a,b,c,);",
     NULL
   };
   // clang-format on
 
   static const ParserFlag always_flags[] = {kAllowHarmonyTrailingCommas};
   RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
                     arraysize(always_flags));
 }