JitCommon/JitCache: Make JitBlock's checkedEntry and normalEntry members non-const pointers

In both cases of the x64 and AArch64 JITs, these would have const casted
away from them, followed by them being placed within an emitter and
having breakpoint instructions written in them.

In this case, we shouldn't be using const period if we're writing to the
emitted data.

Source/Core/Core/PowerPC/CachedInterpreter/CachedInterpreter.cpp

@@ -71,9 +71,9 @@ void CachedInterpreter::Shutdown()
   m_block_cache.Shutdown();
 }
 
-const u8* CachedInterpreter::GetCodePtr() const
+u8* CachedInterpreter::GetCodePtr()
 {
-  return reinterpret_cast<const u8*>(m_code.data() + m_code.size());
+  return reinterpret_cast<u8*>(m_code.data() + m_code.size());
 }
 
 void CachedInterpreter::ExecuteOneBlock()

Source/Core/Core/PowerPC/CachedInterpreter/CachedInterpreter.h

@@ -35,7 +35,7 @@ public:
 private:
   struct Instruction;
 
-  const u8* GetCodePtr() const;
+  u8* GetCodePtr();
   void ExecuteOneBlock();
 
   bool HandleFunctionHooking(u32 address);