Re-indent stack-trace examples for Throwable.printStackTrace

1. Indentation in stack-trace output is significant. The cause of an exception is output on the same level of indentation as that of the exception. A suppressed exception is output at a deeper level of indentation than that of the containing exception. The last example for Throwable.printStackTrace violates this.

2. Indentation in examples for Throwable.printStackTrace that relate to suppressed exceptions is inconsistent with that of cause exceptions.