ci: drop unnecessary rename of *.log into *.log.txt

GitLab added *.log to the allow list back in 11.4 (October 2018 [1]),
but also both GitLab's code and this workaround have been broken anyway
for a very long time now (they just serve everything as `content-type:
application/octet-stream`), so let's just drop it.

[1]: 129a60e79d

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36556>

.gitlab-ci.yml

@@ -149,10 +149,6 @@ default:
       . ${SCRIPTS_DIR}/setup-test-env.sh
     - eval "$S3_JWT_FILE_SCRIPT"
 
-  after_script:
-    # Work around https://gitlab.com/gitlab-org/gitlab/-/issues/20338
-    - find -name '*.log' -exec mv {} {}.txt \;
-
   # Retry when job fails. Failed jobs can be found in the Mesa CI Daily Reports:
   # https://gitlab.freedesktop.org/mesa/mesa/-/issues/?sort=created_date&state=opened&label_name%5B%5D=CI%20daily
   retry:

.gitlab-ci/build/gitlab-ci-inc.yml

@@ -70,7 +70,6 @@
       fi
   after_script:
     - if test -x /usr/bin/ccache; then ccache --show-stats | grep "Hits:"; fi
-    - !reference [default, after_script]
 
 .build-windows:
   extends: