tests: Renaming tests to include dash between words

tests: Renaming tests to include dash between words

In `gem/hello_se/test_hello_se.py`, test suites were being generated
with no space between the word "test" and the test name. A dash has now
been added to make this a more readable.

Change-Id: I9d115a5941cc28af5476175fcbf2bd6940920291
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23025
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>