tests: [WIP] add unit tests for some of the instructions

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

include/cpu/cpu.hh

@@ -35,7 +35,7 @@ class Cpu {
     bool is_flushed;
 
     void chg_mode(const Mode to);
-    void exec_arm(const ArmInstruction instruction);
+    void exec_arm(const arm::ArmInstruction instruction);
 
     struct {
         std::array<uint32_t, GPR_COUNT - GPR_FIQ_FIRST - 1> fiq;