Use 4 workers on dump bot

Bug: b/297302759
Change-Id: Iac13480e5504e09deeedf1ec4938eb3e46d060ba
diff --git a/infra/config/global/main.star b/infra/config/global/main.star
index e57d037..4b827a3 100755
--- a/infra/config/global/main.star
+++ b/infra/config/global/main.star
@@ -379,7 +379,7 @@
   for release in ["", "_release"]:
       properties = {
           "builder_group" : "internal.client.r8",
-          "test_options" : ["--bot"],
+          "test_options" : ["--bot", "--workers", "4"],
           "test_wrapper" : "tools/run_on_app_dump.py"
       }
       name = "linux-run-on-app-dump" + release