Make VM actually check for ABI compatibility when consuming kernel files

[mkustermann]

Right now we have a vm-dartkb-linux-release-x64-abi and tools/VERSION with two ABI numbers in it (ABI_VERSION and OLDEST_SUPPORTED_ABI_VERSION). If the former bot turns red we just bump one or both abi numbers.

Then we have runtime/vm/kernel_binary.h which contains a kMinSupportedKernelFormatVersion and kMaxSupportedKernelFormatVersion. Though the kernel format hasn't had a breaking change in a long time, the [min,max] is [18,35] atm, so the format itself is not breaking very often.

When the VM consumes kernel files it will in fact check whether the given kernel files lie within the kMinSupported.* and kMaxSupported* range.
=> The VM will refuse to load incompatible kernel versions (it returns dart_api.h errors) - which is good.

Though the VM needs more than just a kernel file it can read and understand. It also expects the contents of kernel files to have certain contents. This is a tight contract between dart:* libraries and VM. Adding/Removing native methods, ... can break this contract. For this reason (I suppose) we have the ABI bots.
=> Yet the VM does not check what ABI a kernel file has when consuming it. It will simply crash if the assumptions are not met (see e.g. b/142533773).

Without the VM actually checking the ABI version when consuming kernel files, what is the purpose of the ABI bot?

I assume the answer is that we should embed the ABI version in the kernel files, embedding min/max ABI versions in the VM and start checking compatibility.

/cc @mraleph @a-siva

[devoncarew]

Bumping to P1 as per #41913 (comment).

[natebosch]

I think this has been done now with the SDK hash stuff. Should we close this?