chore: add CPU usage and RSS SLO for macrobenchmarks

PR #14205 introduced a significant performance regression, where the
profiler created a thread which consumed an entire CPU core spinning in
a tight loop. Our macrobenchmarks captured this increased CPU usage, but
we didn't have any SLOs defined. This commit adds an SLO for CPU usage
based on the typical CPU usage prior to that regression. This commit
also adds an RSS SLO, again based on typical usage.

Author: nsrip-dd

.gitlab/benchmarks/bp-runner.macrobenchmarks.fail-on-breach.yml

@@ -40,6 +40,10 @@ experiments:
             thresholds:
               - agg_http_req_duration_p50 < 85 ms
               - agg_http_req_duration_p95 < 95 ms
+          - name: normal_operation/tracing-profiling-enabled/python-server-utilization
+            thresholds:
+              - cpu_usage_percentage < 215%
+              - rss < 1100 MB
           - name: high_load/tracing-profiling-enabled
             thresholds:
               - throughput > 30.0 op/s