Update comments in a test.

This is a follow-up of:
https://chromium-review.googlesource.com/c/chromium/src/+/1688957
One comment was backward.

Bug: 981339
Change-Id: I27e58a0b6a115fc4d7f3a7e9edcb9ff934dd6213
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1746246Reviewed-by: Lowell Manners <lowell@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685511}

content/browser/frame_host/render_frame_host_manager_browsertest.cc

@@ -6453,14 +6453,14 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostManagerTest,
   // Only B4 is deleted. B2 and B3 are still there in a "crashed" state.
   delete_b4.WaitUntilDeleted();
 
-  // A1 and C5 RenderFrameImpl are gone.
+  // B2, B3, B4 RenderFrame are gone.
   EXPECT_FALSE(delete_a1.deleted());
   EXPECT_TRUE(delete_b2.deleted());
   EXPECT_TRUE(delete_b3.deleted());
   EXPECT_TRUE(delete_b4.deleted());
   EXPECT_FALSE(delete_c5.deleted());
 
-  // B2 and B3 are still there, but not B4.
+  // B2 and B3 RenderFrameHost are still there, but B4 is definitely gone.
   ASSERT_EQ(3u, a1->child_count());
   EXPECT_EQ(b2, a1->child_at(0)->current_frame_host());
   EXPECT_EQ(b3, a1->child_at(1)->current_frame_host());