Add tests that public and private static fields are unsupported

test/language/statements/class/static-private-fields-unsupported.js

+// Copyright (C) 2017 Igalia, S. L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Static private fields are not supported
+features: [class, class-fields-private]
+---*/
+
+assert.throws.early(SyntaxError, "class C { static #field; }");
+assert.throws.early(SyntaxError, "class C { static #field = 0; }");
+

test/language/statements/class/static-public-fields-unsupported.js

+// Copyright (C) 2017 Igalia, S. L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Static public fields are not supported
+features: [class, class-fields-public]
+---*/
+
+assert.throws.early(SyntaxError, "class C { static field; }");
+assert.throws.early(SyntaxError, "class C { static field = 0; }");
+assert.throws.early(SyntaxError, "class C { static ['field']; }");
+assert.throws.early(SyntaxError, "class C { static ['field'] = 0; }");