Add missing write barrier to env_copy()

Previously, the following crashed with
`vm_assert_env:imemo_type_p(obj, imemo_env)` due to missing a missing
WB:

    o = Object.new
    def o.foo(n)
      freeze

      GC.stress = 1

      # inflate block nesting get an imemo_env for each level
      n.tap do |i|
        i.tap do |local|
          return Ractor.make_shareable(-> do
            local + i + n
          end)
        end
      end
    ensure
      GC.stress = false
      GC.verify_internal_consistency
    end

    p o.foo(1)[]

By the time the recursive env_copy() call returns, `copied_env` could
have aged or have turned greyed, so we need a WB for the
`ep[VM_ENV_DATA_INDEX_SPECVAL]` assignment which adds an edge.

Fix: 674eb7df7f409099f33da77293d9658e09b470d6

0 files changed, 0 insertions, 0 deletions