[binutils-gdb] Eliminate target_has_exited

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 436411b1c6cb93541fd502321cf5470fe0392b91 ***

Author: Pedro Alves <palves@redhat.com>
Branch: master
Commit: 436411b1c6cb93541fd502321cf5470fe0392b91

Eliminate target_has_exited

Nothing uses this.

gdb/ChangeLog:
2018-04-12  Pedro Alves  <palves@redhat.com>

	* target.h (target_ops::to_has_exited): Delete.
	(target_has_exited): Delete.
	* target-delegates.c: Regenerate.