WOW64: Call Wow64ProcessPendingCrossProcessItems on syscalls

This is needed to handle code invalidation requests sent by external
processes.

Source/Windows/Defs/wow64.def

@@ -22,12 +22,13 @@ EXPORTS
   Wow64PassExceptionToGuest @16
   Wow64PrepareForDebuggerAttach @17 PRIVATE
   Wow64PrepareForException @18
-  Wow64RaiseException @19
-  Wow64ShallowThunkAllocObjectAttributes32TO64_FNC @20 PRIVATE
-  Wow64ShallowThunkAllocSecurityQualityOfService32TO64_FNC @21 PRIVATE
-  Wow64ShallowThunkSIZE_T32TO64 @22 PRIVATE
-  Wow64ShallowThunkSIZE_T64TO32 @23 PRIVATE
-  Wow64SuspendLocalThread @24
-  Wow64SystemServiceEx @25
-  Wow64ValidateUserCallTarget @26 PRIVATE
-  Wow64ValidateUserCallTargetFilter @27 PRIVATE
+  Wow64ProcessPendingCrossProcessItems @19
+  Wow64RaiseException @20
+  Wow64ShallowThunkAllocObjectAttributes32TO64_FNC @21 PRIVATE
+  Wow64ShallowThunkAllocSecurityQualityOfService32TO64_FNC @22 PRIVATE
+  Wow64ShallowThunkSIZE_T32TO64 @23 PRIVATE
+  Wow64ShallowThunkSIZE_T64TO32 @24 PRIVATE
+  Wow64SuspendLocalThread @25 PRIVATE
+  Wow64SystemServiceEx @26
+  Wow64ValidateUserCallTarget @27 PRIVATE
+  Wow64ValidateUserCallTargetFilter @28 PRIVATE

Source/Windows/WOW64/Module.cpp

@@ -460,6 +460,7 @@ public:
       const uint64_t EntryRAX = Frame->State.gregs[FEXCore::X86State::REG_RAX];
 
       Context::UnlockJITContext();
+      Wow64ProcessPendingCrossProcessItems();
       ReturnRAX = static_cast<uint64_t>(Wow64SystemServiceEx(static_cast<UINT>(EntryRAX),
                                                              reinterpret_cast<UINT *>(ReturnRSP + 4)));
       Context::LockJITContext();

Source/Windows/include/winternl.h

@@ -90,6 +90,7 @@ typedef enum _MEMORY_INFORMATION_CLASS {
 } MEMORY_INFORMATION_CLASS;
 
 NTSTATUS WINAPI Wow64SystemServiceEx(UINT,UINT*);
+void WINAPI Wow64ProcessPendingCrossProcessItems(void);
 
 NTSTATUS WINAPI RtlWow64SetThreadContext(HANDLE,const WOW64_CONTEXT*);
 NTSTATUS WINAPI RtlWow64GetThreadContext(HANDLE,WOW64_CONTEXT*);