verify.cc (state::enter_subroutine): New method.

verify.cc (state::enter_subroutine): New method.

	* verify.cc (state::enter_subroutine): New method.
	(handle_jsr_insn): Use it.
	(state::merge): When processing a `ret', correctly use
	subroutine's state to determine which local variables have
	changed.
	(push_exception_jump): Don't let stack overflow.

From-SVN: r49388