Add an option to crash a sample app to test crash reporter plugin

Summary: As per the title

Reviewed By: jknoxville

Differential Revision: D14168217

fbshipit-source-id: c138a4d5c3258f094436a2b09fd18130539a866c

iOS/Sample/MainViewController.mm

@@ -55,4 +55,9 @@
     [self.navigationController pushViewController:communicationDemoViewController animated:true];
 }
 
+- (IBAction)tappedCauseCrash:(UIButton *)sender {
+  NSArray *arr = @[];
+  [arr objectAtIndex:10];
+}
+
 @end