Reduce runs_per_tests for master Foundry builds to 1
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
index ed5caa4..882e4df 100644
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
@@ -13,6 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="-c dbg --test_timeout=300,450,1200,3600 --runs_per_test_detects_flakes --runs_per_test=2"
+EXTRA_FLAGS="-c dbg --test_timeout=300,450,1200,3600 --runs_per_test_detects_flakes --runs_per_test=1"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"
 
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
index 66f02a8..85f6953 100644
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
@@ -13,5 +13,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="-c opt --test_timeout=300,450,1200,3600 --runs_per_test_detects_flakes --runs_per_test=2"
+EXTRA_FLAGS="-c opt --test_timeout=300,450,1200,3600 --runs_per_test_detects_flakes --runs_per_test=1"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"