Feature detect function name property in issue 950

IE 11 does not support the name property on functions. With this change
the test case for issue 950 is only executed if the name property is
supported.

test/issues/issues-test.js

@@ -123,30 +123,33 @@ describe("issues", function () {
     });
 
     describe("#950 - first execution of a spy as a method renames that spy", function () {
-        it("should not rename spies", function () {
-            var expectedName = "proxy";
+        function bob() {}
 
-            function bob() {}
-            var spy = sinon.spy(bob);
+        // IE 11 does not support the function name property
+        if (bob.name) {
+            it("should not rename spies", function () {
+                var expectedName = "proxy";
+                var spy = sinon.spy(bob);
 
-            assert.equals(spy.name, expectedName);
+                assert.equals(spy.name, expectedName);
 
-            var obj = { methodName: spy };
-            assert.equals(spy.name, expectedName);
+                var obj = { methodName: spy };
+                assert.equals(spy.name, expectedName);
 
-            spy();
-            assert.equals(spy.name, expectedName);
+                spy();
+                assert.equals(spy.name, expectedName);
 
-            obj.methodName.call(null);
-            assert.equals(spy.name, expectedName);
+                obj.methodName.call(null);
+                assert.equals(spy.name, expectedName);
 
-            obj.methodName();
-            assert.equals(spy.name, expectedName);
+                obj.methodName();
+                assert.equals(spy.name, expectedName);
 
-            obj.otherProp = spy;
-            obj.otherProp();
-            assert.equals(spy.name, expectedName);
-        });
+                obj.otherProp = spy;
+                obj.otherProp();
+                assert.equals(spy.name, expectedName);
+            });
+        }
     });
 
     describe("#1026", function () {