RNTesterSnapshotTests update ios snapshot images due to layout changes (#23152)

Summary:
Thank you for sending the PR! We appreciate you spending the time to work on these changes.
Help us understand your motivation by explaining why you decided to make this change:

Changelog:
----------
Currently ci in master fail for `test_ios`. Due to tests in `RNTesterSnapshotTests`. (Related to https://github.com/facebook/react-native/issues/23108)
Root cause is layout in RNTest was changed and snapshot is not updated to reflect changes. https://user-images.githubusercontent.com/4032276/51730680-06609480-20ab-11e9-88cb-d4113e2819f2.png

Reference: https://circleci.com/gh/facebook/react-native/68285?utm_campaign=vcs-integration-link&utm_medium=referral&utm_source=github-build-link

[iOS] [Fixed] - Fix test ios in ci
Pull Request resolved: https://github.com/facebook/react-native/pull/23152

Differential Revision: D13817049

Pulled By: cpojer

fbshipit-source-id: 7df8b6744ae91cf9be0ef9eee476c8f1565ae1f6

RNTester/RNTesterIntegrationTests/RNTesterSnapshotTests.m

@@ -23,10 +23,8 @@
 - (void)setUp
 {
   _runner = RCTInitRunnerForApp(@"RNTester/js/RNTesterApp.ios", nil, nil);
-  if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 11) {
-    _runner.testSuffix = @"-iOS11";
-  } else if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 10) {
-    _runner.testSuffix = @"-iOS10";
+  if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 10) {
+    _runner.testSuffix = [NSString stringWithFormat:@"-iOS%d", UIDevice.currentDevice.systemVersion.intValue];
   }
   _runner.recordMode = NO;
 }