Refactor TSAN system test job definitions

Multiple YAML keys have identical values for both TSAN system test job
definitions.  Extract these common keys to a YAML anchor and use it in
TSAN system test job definitions to reduce code duplication.

.gitlab-ci.yml

@@ -260,7 +260,7 @@ stages:
     export SLOT=$(sh -x bin/tests/prepare-softhsm2.sh)
     test -n "${SLOT}" && test "${SLOT}" -gt 0
 
-.system_test: &system_test_job
+.system_test_common: &system_test_common
   <<: *default_triggering_rules
   stage: system
   before_script:
@@ -269,11 +269,27 @@ stages:
   script:
     - ( cd bin/tests/system && make -j${TEST_PARALLEL_JOBS:-1} -k test V=1 )
     - test -s bin/tests/system/systests.output
+
+.system_test: &system_test_job
+  <<: *system_test_common
   artifacts:
     untracked: true
     expire_in: "1 day"
     when: on_failure
 
+.system_test_tsan: &system_test_tsan_job
+  <<: *system_test_common
+  allow_failure: true
+  after_script:
+    - find bin -name 'tsan.*' -exec python3 util/parse_tsan.py {} \;
+  artifacts:
+    expire_in: "1 day"
+    paths:
+      - bin/tests/system/*/tsan.*
+      - bin/tests/system/*/*/tsan.*
+      - tsan/
+    when: on_failure
+
 .kyua_report: &kyua_report_html |
   kyua --logfile /dev/null report-html \
        --force \
@@ -916,20 +932,10 @@ system:gcc:tsan:
   variables:
     TSAN_OPTIONS: ${TSAN_OPTIONS_COMMON}
   <<: *base_image
-  <<: *system_test_job
+  <<: *system_test_tsan_job
   needs:
     - job: gcc:tsan
       artifacts: true
-  allow_failure: true
-  after_script:
-    - find bin -name 'tsan.*' -exec python3 util/parse_tsan.py {} \;
-  artifacts:
-    expire_in: "1 day"
-    paths:
-      - bin/tests/system/*/tsan.*
-      - bin/tests/system/*/*/tsan.*
-      - tsan/
-    when: on_failure
 
 unit:gcc:tsan:
   variables:
@@ -965,20 +971,10 @@ system:clang:tsan:
   variables:
     TSAN_OPTIONS: ${TSAN_OPTIONS_COMMON}
   <<: *base_image
-  <<: *system_test_job
+  <<: *system_test_tsan_job
   needs:
     - job: clang:tsan
       artifacts: true
-  allow_failure: true
-  after_script:
-    - find bin -name 'tsan.*' -exec python3 util/parse_tsan.py {} \;
-  artifacts:
-    expire_in: "1 day"
-    paths:
-      - bin/tests/system/*/tsan.*
-      - bin/tests/system/*/*/tsan.*
-      - tsan/
-    when: on_failure
 
 unit:clang:tsan:
   variables: