Don't build bazel in incompatible flags pipeline

Change-Id: Ic7c05812eddd9deda8a67536d5277fdd277956d8
diff --git a/buildkite/bazelci.py b/buildkite/bazelci.py
index 683b6d2..2c51048 100644
--- a/buildkite/bazelci.py
+++ b/buildkite/bazelci.py
@@ -1411,12 +1411,13 @@
     if info_box_step is not None:
         pipeline_steps.append(info_box_step)
 
-    for platform in configs:
-        pipeline_steps.append(
-            bazel_build_step(platform, "Bazel", http_config, file_config, build_only=True)
-        )
+    if not test_incompatible_flags:
+        for platform in configs:
+            pipeline_steps.append(
+                bazel_build_step(platform, "Bazel", http_config, file_config, build_only=True)
+            )
 
-    pipeline_steps.append("wait")
+        pipeline_steps.append("wait")
 
     incompatible_flags = None
     if test_incompatible_flags: