Failures on Debian-s390x-native-gdbserver-m64, branch master

[sergiodj+buildbot@sergiodj.net]

Buildslave:
	debian-jessie-s390x-1

Full Build URL:
	<http://gdb-build.sergiodj.net/builders/Debian-s390x-native-gdbserver-m64/builds/4126>

Commit(s) tested:
	3e00d44febb8093d8dc0e6842b975afb194c4fd1

Author(s) (in the same order as the commits):
	Simon Marchi <simon.marchi@ericsson.com>

Subject:
	Remove some unnecessary inferior_ptid setting/restoring when fetching/storing registers

Testsuite log (gdb.sum and gdb.log) URL(s):
	<http://gdb-build.sergiodj.net/results/Debian-s390x-native-gdbserver-m64/3e/3e00d44febb8093d8dc0e6842b975afb194c4fd1/>