Introduces Dart_NewFinalizableHandle which does auto delete itself,
but does not allow accessing the weak referenced object.
Issue: https://github.com/dart-lang/sdk/issues/42312
Change-Id: I24ea732925122c453213c4fa3f629761c352f838
Cq-Include-Trybots:dart/try:vm-ffi-android-debug-arm-try,vm-ffi-android-debug-arm64-try,app-kernel-linux-debug-x64-try,vm-kernel-linux-debug-ia32-try,vm-kernel-win-debug-x64-try,vm-kernel-win-debug-ia32-try,vm-kernel-precomp-linux-debug-x64-try,vm-dartkb-linux-release-x64-abi-try,vm-kernel-precomp-android-release-arm64-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-msan-linux-release-x64-try,vm-kernel-precomp-msan-linux-release-x64-try,vm-kernel-linux-release-simarm-try,vm-kernel-linux-release-simarm64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-obfuscate-linux-release-x64-try,dart-sdk-linux-try,analyzer-analysis-server-linux-try,analyzer-linux-release-try,front-end-linux-release-x64-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-mac-debug-x64-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-kernel-nnbd-linux-debug-x64-try,analyzer-nnbd-linux-release-try,front-end-nnbd-linux-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/154695
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
