Add Run Multiple menu items to test item gutter (#1035)

We can add the Run Multiple Times and Run Until Failure menu items onto
the green play button icon in the gutter of the editor. This is in
addition to having it on individual items in the test explorer.

Author: plemarquand

package.json

@@ -612,6 +612,18 @@
       }
     ],
     "menus": {
+      "testing/item/gutter": [
+        {
+          "command": "swift.runTestsMultipleTimes",
+          "group": "testExtras",
+          "when": "testId"
+        },
+        {
+          "command": "swift.runTestsUntilFailure",
+          "group": "testExtras",
+          "when": "testId"
+        }
+      ],
       "testing/item/context": [
         {
           "command": "swift.runTestsMultipleTimes",