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

Source/UnitTests/Core/PageFaultTest.cpp

@@ -9,6 +9,7 @@
 #include "Core/MemTools.h"
 #include "Core/PowerPC/JitCommon/JitBase.h"
 #include "Core/PowerPC/JitInterface.h"
+#include "Core/System.h"
 
 // include order is important
 #include <gtest/gtest.h>  // NOLINT
@@ -25,6 +26,8 @@ enum
 class PageFaultFakeJit : public JitBase
 {
 public:
+  explicit PageFaultFakeJit(Core::System& system) : JitBase(system) {}
+
   // CPUCoreBase methods
   void Init() override {}
   void Shutdown() override {}
@@ -72,7 +75,7 @@ TEST(PageFault, PageFault)
   EXPECT_NE(data, nullptr);
   Common::WriteProtectMemory(data, PAGE_GRAN, false);
 
-  PageFaultFakeJit pfjit;
+  PageFaultFakeJit pfjit(Core::System::GetInstance());
   JitInterface::SetJit(&pfjit);
   pfjit.m_data = data;