workflows: disable cockroach-microbench-ci step for pull requests

This change disbales the CI step for pull requests but this still runs
for push step into the target branch. Also the count of the
microbenchmarks are increased to get more robust results.

Epic: none

Release note: None

.github/workflows/github-actions-essential-ci.yml

@@ -347,6 +347,8 @@ jobs:
         if: always()
   cockroach-microbench-ci:
     runs-on: [ self-hosted, basic_runner_group ]
+    # TODO(sambhav-jain-16): enable this for pull requests also
+    if: ${{ github.event_name == 'push' }}
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v4

build/github/cockroach-microbench-ci.sh

@@ -44,7 +44,7 @@ bazel test //pkg/sql/tests:tests_test \
   --test_sharding_strategy=disabled \
   --test_arg=-test.cpu --test_arg=1 \
   --test_arg=-test.v \
-  --test_arg=-test.count=4 \
+  --test_arg=-test.count=10 \
   --test_arg=-test.benchmem \
   --crdb_test_off \
   --test_output=all > "$log_output_file_path"