tests,configs: Update x86 boot tests/examples with Workload

As of this commit:
https://gem5-review.googlesource.com/c/public/gem5-resources/+/62658
there is an x86-ubuntu-18.04-boot workload.

Where appropriate tests and example scripts have been updated to use
this workload.

Change-Id: I7c9dc8e0e53b1d3f4c365f0382b5f5d4224436f7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62663
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
3 files changed