[ios] Cleanup in recent_tabs_coordinator_unittest.mm after CL1314635

Let's use "test@test.com" to make it more explicit that we're passing
an email address to MakePrimaryAccountAvailable(), and avoid using
an accessor method when we can simply reference an object directly.

Bug: 890825
Change-Id: Id84246d3c07e7494c7b9188000a18277fce92621
Reviewed-on: https://chromium-review.googlesource.com/c/1317862Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Cr-Commit-Position: refs/heads/master@{#605370}

ios/chrome/browser/ui/recent_tabs/recent_tabs_coordinator_unittest.mm

@@ -136,9 +136,9 @@ class RecentTabsTableCoordinatorTest : public BlockCleanupTest {
                       BOOL syncEnabled,
                       BOOL hasForeignSessions) {
     if (signedIn) {
-      identity_test_env()->MakePrimaryAccountAvailable("test");
-    } else if (identity_test_env()->identity_manager()->HasPrimaryAccount()) {
-      identity_test_env()->identity_manager()->ClearPrimaryAccount(
+      identity_test_env_.MakePrimaryAccountAvailable("test@test.com");
+    } else if (identity_test_env_.identity_manager()->HasPrimaryAccount()) {
+      identity_test_env_.identity_manager()->ClearPrimaryAccount(
           identity::IdentityManager::ClearAccountTokensAction::kDefault,
           signin_metrics::SIGNOUT_TEST,
           signin_metrics::SignoutDelete::IGNORE_METRIC);
@@ -183,10 +183,6 @@ class RecentTabsTableCoordinatorTest : public BlockCleanupTest {
     [coordinator_ start];
   }
 
-  identity::IdentityTestEnvironment* identity_test_env() {
-    return &identity_test_env_;
-  }
-
  protected:
   web::TestWebThreadBundle thread_bundle_;
   GoogleServiceAuthError no_error_;