Allow restricting platforms for certain tests
diff --git a/build.json b/build.json
index 06bcd0e..f7a05fa 100644
--- a/build.json
+++ b/build.json
@@ -854,6 +854,9 @@
         "grpc",
         "gpr_test_util",
         "gpr"
+      ],
+      "platforms": [
+        "posix"
       ]
     },
     {