Add Elbrus-2000 (e2k) support

[r-a-sattarov]

Added e2k architecture definition.

[arrowd]

Maybe it'd be worth mentioning that tests are passing like it is done in #361

[tresat]

Sorry for the late reply.

The relevant team will make a decision on merging this.

[asodja]

We figured that we currently can't compile native binaries for this platform (we also can't test on this platform, but that is another issue), so this will have to wait we have a better support for native cross compilation probably with zig as we do in https://github.com/gradle/gradle-fileevents

[r-a-sattarov]

We figured that we currently can't compile native binaries for this platform (we also can't test on this platform, but that is another issue), so this will have to wait we have a better support for native cross compilation probably with zig as we do in https://github.com/gradle/gradle-fileevents

I've commented out lines of code that can't be compiled and tested yet (as is done for riscv arch - e494d6b).
However, a cross compiler (https://dev.mcst.ru/downloads/2026-03-13/cross-sp-public-osl-1.29.16.e2k-v5.linux-6.1_64.tgz) and an emulator qemu-e2k (https://git.openelbrus.ru/mcst/qemu) are available for the e2k architecture.
A fellow enthusiast created GitHub-Action based on them - https://github.com/marketplace/actions/lcc-env