[CI] Reduce FTR and Jest bench runtime

.buildkite/pipelines/pull_request/ftr_bench.yml

@@ -2,7 +2,7 @@ steps:
   - command: .buildkite/scripts/steps/ftr_bench.sh
     label: 'FTR Bench'
     agents:
-      machineType: c2d-standard-16
+      machineType: n4d-standard-16
       zones: northamerica-northeast2-b,us-central1-c,us-central1-a
       diskSizeGb: 200
     key: ftr_bench

src/platform/packages/shared/kbn-ftr-benchmarks/benchmark.config.ts

@@ -45,7 +45,7 @@ const config: InitialBenchConfig = {
       'x-pack/platform/test/functional/apps/lens/open_in_lens/dashboard/config.ts'
     ),
   ],
-  runs: 2,
+  runs: 1,
   timeout: 10 * 300_000,
 };