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Co-authored-by: Jan Kotas <[email protected]>

Author: VSadov

src/coreclr/vm/ceemain.cpp

@@ -894,6 +894,7 @@ void EEStartupHelper()
 #endif
 
         // throws on error
+        _ASSERTE(GetThreadNULLOk() == NULL);
         SetupThread();
 
 #ifdef DEBUGGING_SUPPORTED