Change aoti_cuda in executorch-config.cmake to aoti_cuda_backend (#15726)

As titled.

### Summary
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### Test plan
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Author: larryliu0820

backends/aoti/export.h

@@ -9,9 +9,10 @@
 #pragma once
 
 // Define export macro for Windows DLL
-// When building the aoti_cuda library, EXPORT_AOTI_FUNCTIONS is defined by
-// CMake, which causes this macro to export symbols using __declspec(dllexport).
-// When consuming the library, the macro imports symbols using
+// When building the aoti_cuda_backend library, EXPORT_AOTI_FUNCTIONS is defined
+// by CMake, which causes this macro to export symbols using
+// __declspec(dllexport). When consuming the library, the macro imports symbols
+// using
 // __declspec(dllimport). On non-Windows platforms, the macro is empty and has
 // no effect.
 #ifdef _WIN32

examples/models/gemma3/CMakeLists.txt

@@ -102,8 +102,8 @@ list(
 # Link CUDA backend
 if(EXECUTORCH_BUILD_CUDA)
   find_package(CUDAToolkit REQUIRED)
-  list(APPEND link_libraries aoti_cuda)
-  executorch_target_link_options_shared_lib(aoti_cuda)
+  list(APPEND link_libraries aoti_cuda_backend)
+  executorch_target_link_options_shared_lib(aoti_cuda_backend)
 endif()
 
 # Add tokenizers

examples/models/whisper/CMakeLists.txt

@@ -69,8 +69,8 @@ list(
 # Link CUDA backend
 if(EXECUTORCH_BUILD_CUDA)
   find_package(CUDAToolkit REQUIRED)
-  list(APPEND _link_libraries aoti_cuda)
-  executorch_target_link_options_shared_lib(aoti_cuda)
+  list(APPEND _link_libraries aoti_cuda_backend)
+  executorch_target_link_options_shared_lib(aoti_cuda_backend)
 endif()
 
 if(EXECUTORCH_BUILD_METAL)

tools/cmake/executorch-config.cmake

@@ -53,7 +53,7 @@ set(EXECUTORCH_FOUND ON)
 include("${CMAKE_CURRENT_LIST_DIR}/ExecuTorchTargets.cmake")
 
 set(optional_lib_list
-    aoti_cuda
+    aoti_cuda_backend
     flatccrt
     etdump
     bundled_program