Initial entropy run should be context specific

Otherwise test influence each other.
Is a change to the context but only if the NV seed feature is enabled

include/mbedtls/entropy.h

@@ -134,6 +134,9 @@ typedef struct
 #if defined(MBEDTLS_THREADING_C)
     mbedtls_threading_mutex_t mutex;    /*!< mutex                  */
 #endif
+#if defined(MBEDTLS_ENTROPY_NV_SEED)
+    int initial_entropy_run;
+#endif
 }
 mbedtls_entropy_context;