ci/b2c: identify dut by its id instead of its tags

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26653>

.gitlab-ci/b2c/b2c.yml.jinja2.jinja2

@@ -2,10 +2,7 @@ version: 1
 
 # Rules to match for a machine to qualify
 target:
-  tags:
-{% for tag in tags %}
-    - '{{ tag | trim }}'
-{% endfor %}
+  id: '{{ ci_runner_id }}'
 
 timeouts:
   first_console_activity:  # This limits the time it can take to receive the first console log

.gitlab-ci/b2c/generate_b2c.py

@@ -23,7 +23,6 @@
 
 from jinja2 import Environment, FileSystemLoader
 from os import environ, path
-import json
 
 
 # Pass all the environment variables prefixed by B2C_
@@ -38,10 +37,7 @@ env = Environment(loader=FileSystemLoader(path.dirname(values['job_template'])),
 template = env.get_template(path.basename(values['job_template']))
 
 values['ci_job_id'] = environ['CI_JOB_ID']
-try:
-    values['tags'] = json.loads(environ['CI_RUNNER_TAGS'])
-except json.decoder.JSONDecodeError:
-    values['tags'] = environ['CI_RUNNER_TAGS'].split(",")
+values['ci_runner_id'] = environ['CI_RUNNER_ID']
 values['job_volume_exclusions'] = [excl for excl in values['job_volume_exclusions'].split(",") if excl]
 values['working_dir'] = environ['CI_PROJECT_DIR']