[dynarmic] Fix building of tests (#3599)

Proposed-by: lizzie lizzie@eden-emu.dev
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3599
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Co-authored-by: DraVee <dravee@eden-emu.dev>
Co-committed-by: DraVee <dravee@eden-emu.dev>

src/dynarmic/tests/print_info.cpp

@@ -53,9 +53,7 @@ std::string_view GetNameOfA32Instruction(u32 instruction) {
 }
 
 std::string_view GetNameOfA64Instruction(u32 instruction) {
-    if (auto const decoder = A64::Decode<A64::TranslatorVisitor>(instruction))
-        return *A64::GetName<A64::TranslatorVisitor>(instruction);
-    return "<null>";
+    return *A64::GetName<A64::TranslatorVisitor>(instruction);
 }
 
 void PrintA32Instruction(u32 instruction) {