Remove obsolete Bazel spawn strategies

After the latest Bazel upgrade, the --spawn_strategy=standalone
doesn't show the output of the subprocess created, making the
troubleshoot of the failures impossible.

Change-Id: I8308d347739cb06469395b8cf3bce5f982ccc32b
diff --git a/roles/bazelisk-build/tasks/main.yaml b/roles/bazelisk-build/tasks/main.yaml
index c06e0af..7b07360 100644
--- a/roles/bazelisk-build/tasks/main.yaml
+++ b/roles/bazelisk-build/tasks/main.yaml
@@ -2,7 +2,7 @@
   shell: |
     java -fullversion
     {{ bazelisk_executable }} version
-    {{ bazelisk_executable }} build --spawn_strategy=standalone --genrule_strategy=standalone --java_toolchain=//tools:error_prone_warnings_toolchain {{ bazelisk_targets }}
+    {{ bazelisk_executable }} build --java_toolchain=//tools:error_prone_warnings_toolchain {{ bazelisk_targets }}
   args:
     executable: /bin/bash
     chdir: "{{ zuul_work_dir }}"