ConstProp: treat StoreContext as zeroable

todo: FPR equivalent.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

FEXCore/Source/Interface/Core/JIT/Arm64/MemoryOps.cpp

@@ -52,7 +52,7 @@ DEF_OP(StoreContext) {
   const auto OpSize = IROp->Size;
 
   if (Op->Class == FEXCore::IR::GPRClass) {
-    auto Src = GetReg(Op->Value.ID());
+    auto Src = GetZeroableReg(Op->Value);
 
     switch (OpSize) {
     case 1: strb(Src, STATE, Op->Offset); break;

FEXCore/Source/Interface/IR/Passes/ConstProp.cpp

@@ -629,7 +629,8 @@ void ConstProp::ConstantInlining(IREmitter* IREmit, const IRListView& CurrentIR)
       break;
     }
     case OP_ADC:
-    case OP_ADCWITHFLAGS: {
+    case OP_ADCWITHFLAGS:
+    case OP_STORECONTEXT: {
       uint64_t Constant1 {};
       if (IREmit->IsValueConstant(IROp->Args[0], &Constant1)) {
         if (Constant1 == 0) {