tests: Improve Resource Downloader Test Suite

Theses improvements are:

1. Renames the test suite to the correct "ResourceDownloaderTestSuite".
   This was correctly named MD5FileTestSuite due to a copy-and-paste
   error.
2. Adds the `setUpClass` and `tearDownClass` from the Python's unittest
   framework. These are used to create the simple "resources.json" file
   used for testing, set the "GEM5_RESOURCE_JSON", and delete these when
   the test is complete.
3. The tests have been updated to utilize the improvements added in 2.

Change-Id: Ia54e45892452bf23b54c8b5a6bb4a94910d83c5f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62651
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed