Fix a test so that we don't get duplicate declaration errors.

tests/cases/conformance/es6/Symbols/symbolDeclarationEmit11.ts

@@ -2,7 +2,7 @@
 //@declaration: true
 class C {
     static [Symbol.iterator] = 0;
-    static [Symbol.toPrimitive]() { }
+    static [Symbol.isConcatSpreadable]() { }
     static get [Symbol.toPrimitive]() { return ""; }
     static set [Symbol.toPrimitive](x) { }
 }