Fix: methods cannot be used as constructor

The spec says that invoking a method as a constructor is not valid,
but invoking normal functions is. This is, for example, `node`:

```js
> o = { method() {}, notAMethod: function() {} }
{ method: [Function: method], notAMethod: [Function: notAMethod] }
> new o.method()
Uncaught TypeError: o.method is not a constructor
> new o.notAMethod()
notAMethod {}
```

This PR implements the same behavior in Rhino, and fixes #1299.

rhino/src/main/java/org/mozilla/javascript/BaseFunction.java

@@ -408,6 +408,11 @@ public Object call(Context cx, Scriptable scope, Scriptable thisObj, Object[] ar
 
     @Override
     public Scriptable construct(Context cx, Scriptable scope, Object[] args) {
+        if (cx.getLanguageVersion() >= Context.VERSION_ES6 && this.getHomeObject() != null) {
+            // Only methods have home objects associated with them
+            throw ScriptRuntime.typeErrorById("msg.not.ctor", getFunctionName());
+        }
+
         Scriptable result = createObject(cx, scope);
         if (result != null) {
             Object val = call(cx, scope, result, args);

rhino/src/main/java/org/mozilla/javascript/Interpreter.java

@@ -2006,6 +2006,14 @@ private static Object interpretLoop(Context cx, CallFrame frame, Object throwabl
                                     if (lhs instanceof InterpretedFunction) {
                                         InterpretedFunction f = (InterpretedFunction) lhs;
                                         if (frame.fnOrScript.securityDomain == f.securityDomain) {
+                                            if (cx.getLanguageVersion() >= Context.VERSION_ES6
+                                                    && f.getHomeObject() != null) {
+                                                // Only methods have home objects associated with
+                                                // them
+                                                throw ScriptRuntime.typeErrorById(
+                                                        "msg.not.ctor", f.getFunctionName());
+                                            }
+
                                             Scriptable newInstance =
                                                     f.createObject(cx, frame.scope);
                                             CallFrame calleeFrame =

tests/src/test/java/org/mozilla/javascript/tests/harmony/MethodDefinitionTest.java

@@ -4,8 +4,11 @@
 
 package org.mozilla.javascript.tests.harmony;
 
+import org.mozilla.javascript.Context;
+import org.mozilla.javascript.drivers.LanguageVersion;
 import org.mozilla.javascript.drivers.RhinoTest;
 import org.mozilla.javascript.drivers.ScriptTestsBase;
 
 @RhinoTest("testsrc/jstests/harmony/method-definition.js")
+@LanguageVersion(Context.VERSION_ES6)
 public class MethodDefinitionTest extends ScriptTestsBase {}

tests/testsrc/jstests/harmony/method-definition.js

@@ -63,7 +63,10 @@ assertEquals(123, {
 }.abc());
 
 // Method is the kind of function, that is non-constructor.
-// assertThrows('new (({ a() {} }).a)', TypeError);
+assertThrows(function() {
+  new (({ a() {} }).a)
+}, TypeError);
+assertNotNull(new (({ notAMethod: function() {} }).notAMethod));
 
 var desc = Object.getOwnPropertyDescriptor({
   a() {

tests/testsrc/test262.properties

@@ -957,7 +957,7 @@ built-ins/Number 23/335 (6.87%)
     S9.3.1_A3_T1_U180E.js {unsupported: [u180e]}
     S9.3.1_A3_T2_U180E.js {unsupported: [u180e]}
 
-built-ins/Object 178/3408 (5.22%)
+built-ins/Object 177/3408 (5.19%)
     assign/assignment-to-readonly-property-of-target-must-throw-a-typeerror-exception.js
     assign/not-a-constructor.js
     assign/source-own-prop-error.js
@@ -1530,7 +1530,7 @@ built-ins/Promise 392/631 (62.12%)
     resolve-thenable-deferred.js {unsupported: [async]}
     resolve-thenable-immed.js {unsupported: [async]}
 
-built-ins/Proxy 76/311 (24.44%)
+built-ins/Proxy 73/311 (23.47%)
     construct/arguments-realm.js
     construct/call-parameters.js
     construct/call-parameters-new-target.js
@@ -3146,7 +3146,7 @@ built-ins/undefined 0/8 (0.0%)
 
 ~intl402
 
-language/arguments-object 185/263 (70.34%)
+language/arguments-object 184/263 (69.96%)
     mapped/mapped-arguments-nonconfigurable-3.js non-strict
     mapped/mapped-arguments-nonconfigurable-delete-1.js non-strict
     mapped/mapped-arguments-nonconfigurable-delete-2.js non-strict
@@ -4852,7 +4852,7 @@ language/expressions/new 41/59 (69.49%)
 
 ~language/expressions/new.target
 
-language/expressions/object 719/1169 (61.51%)
+language/expressions/object 717/1169 (61.33%)
     dstr/async-gen-meth-ary-init-iter-close.js {unsupported: [async-iteration, async]}
     dstr/async-gen-meth-ary-init-iter-get-err.js {unsupported: [async-iteration]}
     dstr/async-gen-meth-ary-init-iter-get-err-array-prototype.js {unsupported: [async-iteration]}
@@ -5456,7 +5456,6 @@ language/expressions/object 719/1169 (61.51%)
     method-definition/gen-yield-spread-arr-multiple.js
     method-definition/gen-yield-spread-arr-single.js
     method-definition/gen-yield-spread-obj.js
-    method-definition/generator-invoke-ctor.js
     method-definition/generator-invoke-fn-strict.js non-strict
     method-definition/generator-length-dflt.js
     method-definition/generator-name-prop-string.js
@@ -5475,7 +5474,6 @@ language/expressions/object 719/1169 (61.51%)
     method-definition/meth-eval-var-scope-syntax-err.js non-strict
     method-definition/meth-object-destructuring-param-strict-body.js
     method-definition/meth-rest-param-strict-body.js
-    method-definition/name-invoke-ctor.js
     method-definition/name-invoke-fn-strict.js non-strict
     method-definition/name-length-dflt.js
     method-definition/name-name-prop-string.js