lib: add SafeSet.prototype.toUnsafeSet

This should help with nodejs#57688 and others

Author: ljharb

lib/internal/per_context/primordials.js

@@ -420,6 +420,12 @@ primordials.SafeSet = makeSafe(
   Set,
   class SafeSet extends Set {
     constructor(i) { super(i); } // eslint-disable-line no-useless-constructor
+
+    toUnsafeSet() {
+      const set = new Set();
+      this.forEach((value) => primordials.SetPrototypeAdd(set, value));
+      return set;
+    }
   },
 );
 primordials.SafeWeakSet = makeSafe(