Tests/HIP/WithDefs: Clean up test case

Fix code copied from equivalent CUDA test.

Drop `CMAKE_HIP_ARCHITECTURES=OFF`.  That is already covered by
a dedicated `HIP.ArchitectureOff` test.

Tests/HIP/WithDefs/CMakeLists.txt

@@ -2,12 +2,11 @@
 cmake_minimum_required(VERSION 3.18)
 project (WithDefs HIP)
 
-set(CMAKE_HIP_ARCHITECTURES OFF)
 set(release_compile_defs DEFREL)
 
 #Goal for this example:
-#build a executable that needs to be passed a complex define through add_definitions
-#this verifies we can pass C++ style attributes to hipcc
+#Build an executable that needs to be passed a complex define through add_definitions.
+#Verify we can pass C++ style attributes to the HIP compiler.
 add_definitions("-DPACKED_DEFINE=[[gnu::packed]]")
 
 add_executable(HIPOnlyWithDefs main.hip.cpp)
@@ -17,9 +16,8 @@ target_compile_features(HIPOnlyWithDefs PRIVATE hip_std_17)
 
 target_compile_options(HIPOnlyWithDefs
   PRIVATE
-    --offload-arch=gfx900
     -DFLAG_COMPILE_LANG_$<COMPILE_LANGUAGE>
-    $<$<HIP_COMPILER_ID:Clang>:-DFLAG_LANG_IS_HIP=$<COMPILE_LANGUAGE:HIP>> # Host-only defines are possible only on NVCC.
+    -DFLAG_LANG_IS_HIP=$<COMPILE_LANGUAGE:HIP>
   )
 
 target_compile_definitions(HIPOnlyWithDefs