LibWasm: Add a copy assignment operator to Value

Author: https://github.com/alimpfard
Commit: 85794f8244
Pull-request: https://github.com/SerenityOS/serenity/pull/7482
Reviewed-by: https://github.com/ADKaster

Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.h

@@ -108,6 +108,13 @@ public:
         return *this;
     }
 
+    Value& operator=(const Value& value)
+    {
+        m_value = value.m_value;
+        m_type = value.m_type;
+        return *this;
+    }
+
     template<typename T>
     Optional<T> to()
     {