use ovrsource libtorch in executorch

Summary: We need ovrsource libtorch in arvr mode.

Differential Revision: D66526578

Author: lg-zhang

extension/pytree/aten_util/targets.bzl

@@ -1,4 +1,5 @@
 load("@fbsource//xplat/executorch/build:runtime_wrapper.bzl", "runtime")
+load("@fbsource//tools/build_defs:fbsource_utils.bzl", "is_arvr_mode")
 
 def define_common_targets():
     """Defines targets that should be shared between fbcode and xplat.
@@ -26,7 +27,9 @@ def define_common_targets():
             "//caffe2/c10:c10",
         ],
         xplat_deps = [
+            "fbsource//xplat/caffe2:libtorch_mobile_ovrsource",
+        ] if is_arvr_mode() else [
             "//xplat/caffe2:torch_mobile_core",
             "//xplat/caffe2/c10:c10",
-        ],
+        ] 
     )