compile-print.exp: xfail->kfail for '@' GDB array operator

compile-print.exp: xfail->kfail for '@' GDB array operator

Patch implementing '@' GDB array operator in GCC has been rejected:
	https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00414.html
and so there is now a GDB tracker to implement it just in GDB:
	https://sourceware.org/bugzilla/show_bug.cgi?id=18489

gdb/testsuite/ChangeLog
2015-06-04  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.compile/compile-print.exp (compile print *vararray@3)
	(compile print *vararrayp@3): Change xfail to kfail compile/18489.