What does this PR do?

Fixes #16007

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• Code changes

How did you verify your code works?

Minimal reproduction from bug now shows expected output:

{
  map: Map(2) {
    "foo": "bar",
    "baz": "qux",
  },
  set: Set(2) {
    "foo",
    "bar",
  },
  foo: {
    bar: {
      set: Set(2) {
        "foo",
        "bar",
      },
    },
  },
}

I wrote automated tests test/regression/issue/16007.test.ts

• I checked the lifetime of memory allocated to verify it's (1) freed and (2) only freed when it should be
• I included a test for the new code, or an existing test covers it
• JSValue used outside outside of the stack is either wrapped in a JSC.Strong or is JSValueProtect'ed
• I wrote TypeScript/JavaScript tests and they pass locally (bun-debug test test-file-name.test)