[turbofan] Don't try to inline non-inlineable functions.

test/mjsunit/compiler/regress-crbug-540593.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --enable-slow-asserts --turbo-inlining
+
+var __f_2 = (function(stdlib) {
+  "use asm";
+  var __v_3 = stdlib.Symbol;
+  function __f_2() { return __v_3(); }
+  return __f_2;
+})(this);
+%OptimizeFunctionOnNextCall(__f_2);
+__f_2();