Add wasm target helpers in a finalizer when adding executable

This way it is able to pick up all of the properties assigned to it
before finalization.

Change-Id: I9da635f8620859a669c4e4d589fff56a3ce42ab9
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtExecutableHelpers.cmake

@@ -140,7 +140,6 @@ function(qt_internal_add_executable name)
 
     if(WASM)
         qt_internal_wasm_add_finalizers("${name}")
-        _qt_internal_wasm_add_target_helpers("${name}")
     endif()
 
     # Check if target needs to be excluded from all target. Also affects qt_install.

cmake/QtWasmHelpers.cmake

@@ -104,6 +104,7 @@ endfunction()
 
 function(qt_internal_wasm_add_finalizers target)
     qt_add_list_file_finalizer(_qt_internal_add_wasm_extra_exported_methods ${target})
+    qt_add_list_file_finalizer(_qt_internal_wasm_add_target_helpers ${target})
 endfunction()