ES6 specific functions should declare a feature.

The String.endsWith and String.includes tests didn't specify either an es6id or a features. Added a features attribute for these tests.

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Fail.js

@@ -8,6 +8,7 @@
 author: Ryan Lewis
 description: endsWith should return false when called on 'word' and passed 'r'.
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Fail_2.js

@@ -10,6 +10,7 @@ description: >
     endsWith should return false when called on 'word' and passed 'd',
     with an endPosition of 3.
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Success.js

@@ -10,6 +10,7 @@ description: >
     endsWith should return true when called on 'word' and passed 'd'
     and with no endPosition (defaults to 4).
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Success_2.js

@@ -10,6 +10,7 @@ description: >
     endsWith should return true when called on 'word' and passed 'd'
     and with an endPosition of 4.
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Success_3.js

@@ -10,6 +10,7 @@ description: >
     endsWith should return true when called on 'word' and passed 'd'
     and with an endPosition of 25.
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/endsWith/String.prototype.endsWith_Success_4.js

@@ -10,6 +10,7 @@ description: >
     endsWith should return true when called on 'word' and passed 'r',
     with an endPosition of 3.
 includes: [runTestCase.js]
+features: [String#endsWith]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_FailBadLocation.js

@@ -10,6 +10,7 @@ description: >
     String should return false if a location is passed that is
     greather than the length of the string.
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_FailLocation.js

@@ -10,6 +10,7 @@ description: >
     String should return false if a letter is not found in the word
     starting from the passed location.
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_FailMissingLetter.js

@@ -8,6 +8,7 @@
 author: Ryan Lewis
 description: String should return false if a letter is not found in the word.
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_Success.js

@@ -10,6 +10,7 @@ description: >
     String should return true when called on 'word' and passed 'w' and
     the location 0.
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_SuccessNoLocation.js

@@ -10,6 +10,7 @@ description: >
     String should return true when called on 'word' and passed 'w' and
     with no location (defaults to 0).
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {

test/built-ins/String/prototype/includes/String.prototype.includes_lengthProp.js

@@ -8,6 +8,7 @@
 author: Ryan Lewis
 description: String should have the property length with size of 1.
 includes: [runTestCase.js]
+features: [String#includes]
 ---*/
 
 function testcase() {