[4.1][SourceKit] Update cherry-picked test case for swift-4.1-branch

Author: rintaro

test/SourceKit/DocumentStructure/structure.swift.response

@@ -1136,24 +1136,13 @@
           key.bodylength: 2,
           key.substructure: [
             {
-              key.kind: source.lang.swift.expr.closure,
+              key.kind: source.lang.swift.stmt.brace,
               key.offset: 1787,
               key.length: 2,
               key.nameoffset: 0,
               key.namelength: 0,
               key.bodyoffset: 1788,
-              key.bodylength: 0,
-              key.substructure: [
-                {
-                  key.kind: source.lang.swift.stmt.brace,
-                  key.offset: 1787,
-                  key.length: 2,
-                  key.nameoffset: 0,
-                  key.namelength: 0,
-                  key.bodyoffset: 1788,
-                  key.bodylength: 0
-                }
-              ]
+              key.bodylength: 0
             }
           ]
         }