[dynarmic] include catch2 and oaknut properly for tests

Signed-off-by: crueter <crueter@eden-emu.dev>

externals/CMakeLists.txt

@@ -32,7 +32,7 @@ if (ARCHITECTURE_x86 OR ARCHITECTURE_x86_64)
 endif()
 
 # Oaknut (also used by Dynarmic, so needs to be added first)
-if (ARCHITECTURE_arm64)
+if (ARCHITECTURE_arm64 OR DYNARMIC_TESTS)
     CPMAddPackage(
         NAME oaknut
         VERSION 2.0.1

src/dynarmic/externals/CMakeLists.txt

@@ -35,7 +35,7 @@ endif()
 # TODO(crueter): dedup
 if (NOT TARGET Catch2::Catch2WithMain)
     if (DYNARMIC_TESTS)
-        add_subdirectory(catch EXCLUDE_FROM_ALL)
+        find_package(Catch2 3.0.1 REQUIRED)
     endif()
 endif()