FEXCore: Constify CTX ptr in InternalThreadState

The CTX pointer in the InternalThreadState object will not and must not
change, since it is associated with that CTX object.

Contify it to codify it.

FEXCore/Source/Interface/Core/Core.cpp

@@ -402,8 +402,6 @@ void ContextImpl::InitializeCompiler(FEXCore::Core::InternalThreadState* Thread)
 
   Dispatcher->InitThreadPointers(Thread);
 
-  Thread->CTX = this;
-
   Thread->PassManager->AddDefaultPasses(this);
   Thread->PassManager->AddDefaultValidationPasses();
 
@@ -418,7 +416,9 @@ void ContextImpl::InitializeCompiler(FEXCore::Core::InternalThreadState* Thread)
 
 FEXCore::Core::InternalThreadState*
 ContextImpl::CreateThread(uint64_t InitialRIP, uint64_t StackPointer, const FEXCore::Core::CPUState* NewThreadState, uint64_t ParentTID) {
-  FEXCore::Core::InternalThreadState* Thread = new FEXCore::Core::InternalThreadState {};
+  FEXCore::Core::InternalThreadState* Thread = new FEXCore::Core::InternalThreadState {
+    .CTX = this,
+  };
 
   Thread->CurrentFrame->State.gregs[X86State::REG_RSP] = StackPointer;
   Thread->CurrentFrame->State.rip = InitialRIP;

FEXCore/include/FEXCore/Debug/InternalThreadState.h

@@ -87,7 +87,7 @@ struct InternalThreadState : public FEXCore::Allocator::FEXAllocOperators {
     std::atomic_bool ThreadSleeping {false};
   } RunningEvents;
 
-  FEXCore::Context::Context* CTX;
+  FEXCore::Context::Context* const CTX;
   std::atomic<SignalEvent> SignalReason {SignalEvent::Nothing};
 
   NonMovableUniquePtr<FEXCore::Threads::Thread> ExecutionThread;