classfields: add tests for forbidden privatenames

test/language/expressions/class/fields-privatename-constructor-err.js

+// Copyright (C) 2017 Valerie Young. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Private class fields early error with StringValue "#constructor"
+esid: sec-class-definitions-static-semantics-early-errors
+features: [class-fields]
+negative:
+  phase: early
+  type: SyntaxError
+info: |
+  ClassElementName : PrivateName;
+    It is a Syntax Error if StringValue of PrivateName is "#constructor".
+---*/
+
+
+throw "Test262: This statement should not be evaluated.";
+
+var C = class {
+   #constructor;
+}

test/language/statements/class/fields-privatename-constructor-err.js

+// Copyright (C) 2017 Valerie Young. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Private class fields early error with StringValue "#constructor"
+esid: sec-class-definitions-static-semantics-early-errors
+features: [class-fields]
+negative:
+  phase: early
+  type: SyntaxError
+info: |
+  ClassElementName : PrivateName;
+    It is a Syntax Error if StringValue of PrivateName is "#constructor".
+---*/
+
+throw "Test262: This statement should not be evaluated.";
+
+class C {
+   #constructor;
+}