Backport #66356

    Port of dotnet/runtime#66356

Author: VSadov

src/vm/threads.h

@@ -3455,6 +3455,14 @@ class Thread: public IUnknown
     static void __stdcall RedirectedHandledJITCaseForGCStress();
 #endif // defined(HAVE_GCCOVER) && USE_REDIRECT_FOR_GCSTRESS
 
+#ifdef _TARGET_X86_
+    // RtlRestoreContext is available on x86, but relatively recently.
+    // RestoreContextSimulated uses SEH machinery for a similar result on legacy OS-es.
+    // This function should not be used on new OS-es as the pattern is not
+    // guaranteed to continue working in the future.
+    static void RestoreContextSimulated(Thread* pThread, CONTEXT* pCtx, void* pFrame, DWORD dwLastError);
+#endif
+
     friend void CPFH_AdjustContextForThreadSuspensionRace(T_CONTEXT *pContext, Thread *pThread);
 #endif // FEATURE_HIJACK && !PLATFORM_UNIX