JitBase: Avoid System::GetInstance() and ppcState.

Source/UnitTests/Core/PowerPC/Jit64Common/ConvertDoubleToSingle.cpp

@@ -11,6 +11,7 @@
 #include "Core/PowerPC/Jit64/Jit.h"
 #include "Core/PowerPC/Jit64Common/Jit64AsmCommon.h"
 #include "Core/PowerPC/Jit64Common/Jit64PowerPCState.h"
+#include "Core/System.h"
 
 #include "../TestValues.h"
 
@@ -22,7 +23,7 @@ namespace
 class TestCommonAsmRoutines : public CommonAsmRoutines
 {
 public:
-  TestCommonAsmRoutines() : CommonAsmRoutines(jit)
+  explicit TestCommonAsmRoutines(Core::System& system) : CommonAsmRoutines(jit), jit(system)
   {
     using namespace Gen;
 
@@ -51,7 +52,7 @@ public:
 
 TEST(Jit64, ConvertDoubleToSingle)
 {
-  TestCommonAsmRoutines routines;
+  TestCommonAsmRoutines routines(Core::System::GetInstance());
 
   for (const u64 input : double_test_values)
   {