c++/8218: Destructors w/arguments.

c++/8218: Destructors w/arguments.

For a long time now, c++/8218 has noted that GDB is printing argument types
for destructors:

(gdb) ptype A
type = class A {
  public:
    ~A(int);
}

This happens because cp_type_print_method_args doesn't ignore artificial
arguments.  [It ignores the first `this' pointer because it simply skips
the first argument for any non-static function.]

This patch fixes this:

(gdb) ptype  A
type = class A {
  public:
    ~A();
}

I've adjusted gdb.cp/templates.exp to account for this and added a new
passing regexp.

gdb/ChangeLog

	PR c++/8218
	* c-typeprint.c (cp_type_print_method_args): Skip artificial arguments.

gdb/testsuite/ChangeLog

	PR c++/8128
	* gdb.cp/templates.exp (test_ptype_of_templates): Remove argument
	type from destructor regexps.
	Add a branch which actually passes the test.
	Adjust "ptype t5i" test names.