qemu-helper-native/systemtap-native: Ensure sysroots are populated with dependencies

qemu-helper-native/systemtap-native: Ensure sysroots are populated with dependencies

As Alex Kanavin found, dependencies aren't always populated, particularly
with the hash equivalence server enabled locally:

'bitbake core-image-minimal' with gtk+ disabled.
can confirm with: $ tmp/work/x86_64-linux/qemu-helper-native/1.0-r1/recipe-sysroot-native/usr/bin/qemu-system-x86_64 -display gtk
qemu-system-x86_64: Display 'gtk' is not available.
Enable gtk in local.conf with: PACKAGECONFIG_append_pn-qemu-system-native = " gtk+"
'bitbake core-image-minimal', without deleting tmp/
$ tmp/work/x86_64-linux/qemu-helper-native/1.0-r1/recipe-sysroot-native/usr/bin/qemu-system-x86_64 -display gtk
qemu-system-x86_64: Display 'gtk' is not available.

This change ensures the dependencies are correctly handled as the full
sysroot is always depended upon even if things come from sstate.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>