cmake: Add application manifests when cross-compiling for Windows

Windows application manifests provide several benefits. However, on the
master branch, the linker generates and embeds manifests only when
building with MSVC.

This change unifies manifest embedding for both native and
cross-compilation.

src/test/CMakeLists.txt

@@ -142,6 +142,8 @@ target_raw_data_sources(test_bitcoin NAMESPACE test::data
   data/asmap.raw
 )
 
+add_windows_application_manifest(test_bitcoin)
+
 target_link_libraries(test_bitcoin
   core_interface
   test_util