[class] Fix typo in test

Reported by @ziyunfei here:
https://twitter.com/ziyunfei/status/936524009528811520

Bug: v8:5367
Change-Id: I2b1bb43dff86f35dec824e275740fce4f0c97b2e
Reviewed-on: https://chromium-review.googlesource.com/802877Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49788}

test/mjsunit/harmony/public-instance-class-fields.js

@@ -270,7 +270,7 @@
   let c = new C;
   assertEquals(1, c.a);
   assertEquals(undefined, c.b);
-  assertEquals(undefined, c.c1);
+  assertEquals(undefined, c[c1]);
 }
 
 {
@@ -315,7 +315,7 @@ function x() {
     assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9], log);
   }
 }
-x();
+x()();
 
 {
   class C {}

test/mjsunit/harmony/public-static-class-fields.js

@@ -262,7 +262,7 @@
 
   assertEquals(1, C.a);
   assertEquals(undefined, C.b);
-  assertEquals(undefined, C.c);
+  assertEquals(undefined, C[c]);
 }
 
 {
@@ -310,7 +310,7 @@ function x() {
     assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9], log);
   }
 }
-x();
+x()();
 
 {
   class C {}