case_tac no longer raises THM exception if goal number is out of range.
case_tac no longer raises THM exception if goal number is out of range.

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle