tests: Fix syntax error in cpu_tests/test.py
tests: Fix syntax error in cpu_tests/test.py

The testsuite was not loaded with the following error:

Exception thrown while loading
<gem5>/tests/gem5/cpu_tests/test.py

Signed-off-by: Giacomo Travaglini <8eef13a4f970e2e9372c8d26ad0737b760f99c02@arm.com>
Change-Id: I1e88b8957bb24471e1bb6113ffc7c78886b6ed70
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39295
Reviewed-by: Hoa Nguyen <a0aa8449aacb303edcb25d6bbe69da9124f010fc@ucdavis.edu>
Maintainer: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5