Update on "use-pt-pinned-commit for test-arm-{backend,reference}-dele…

…gation"

Without this, these builds don't respect the torchgen pinned commit and thus fail with #7546.

Differential Revision: [D67996459](https://our.internmc.facebook.com/intern/diff/D67996459/)

[ghstack-poisoned]

backends/apple/coreml/CMakeLists.txt

@@ -135,7 +135,7 @@ target_include_directories(
 )
 target_include_directories(coremldelegate PRIVATE ${EXECUTORCH_ROOT}/..)
 target_include_directories(coremldelegate PRIVATE ${EXECUTORCH_ROOT}/runtime/core/portable_type)
-target_compile_definitions(coremldelegate C10_USING_CUSTOM_GENERATED_MACROS)
+target_compile_definitions(coremldelegate PRIVATE C10_USING_CUSTOM_GENERATED_MACROS)
 target_link_libraries(coremldelegate PRIVATE executorch_core)
 
 if(EXECUTORCH_BUILD_DEVTOOLS)