See 2e5b783cc6 for details
After the fix for KT-57694 (mostly rewritten JvmMappedScope),
the behavior of loading new JDK 21 members of K2 has been aligned with K1
After it's released, there would be no need in them, but right now
they are unavailable through the toolchain, so we can't require it.
See KT-58765 for tracking
But there should be a dedicated Build configuration with JDK_21_0 env
properly set.
^KT-58716 Fixed