I believe the weekly test failures (example:
https://github.com/gem5/gem5/actions/runs/6832805510/job/18592876184)
are due to a container running out of memory when running the very-long
x86 boot tests. I found that the `-t $(nproc)` flag meant, on our
runners, 4 x86 full system gem5 simulations were being pawned. Locally I
found these gem5 x86 boot sims can reach 4GB in size so I suspect they
eventually grew big enough exceed the 16GB memory of the VM.
I have removed `-t $(nproc)` meaning each execution to see if this fixes
the issue (we may want to use `-t 2` later if the Weeklies take too long
running single-threaded).
30787b59d4