fix: pass remaining riscv isa tests

sim/verilator/memory.h

@@ -31,9 +31,11 @@ public:
     void write64(uint64_t addr, uint64_t data);
 
     uint64_t get_entry_point() const { return entry_point; }
+    uint64_t get_tohost_addr() const { return tohost_addr; }
 
 private:
     uint64_t entry_point;
+    uint64_t tohost_addr;
     uint64_t to_offset(uint64_t addr);
 };