[ci] Run ctest serially on Ubuntu1 for performance metrics.

Ubuntu1 can run only 1 job at a time.

scripts/ci/jobs/build-linux.yml

@@ -100,7 +100,7 @@ build linux debug with sanitizers:
     UBSAN_OPTIONS: "print_stacktrace=1"
     LSAN_OPTIONS: "suppressions=$CI_PROJECT_DIR/scripts/test/leak_sanitizer.suppressions"
 
-.build linux ubuntu: # Temporary disabled until node is updated
+build linux ubuntu perf:
   extends:
     - .template-build-linux
     - .test-artifacts
@@ -109,3 +109,4 @@ build linux debug with sanitizers:
   needs: [meta]
   variables:
     CMAKE_PRESET: release-all
+    CTEST_PARALLEL_LEVEL: 1 # Run ctests serially