Support for global constructors and destructors

All kernel functions in `@llvm.global_ctors` and `@llvm.global_dtors` should have their execution mode marked as, respectively, `Initializer` or `Finalizer`. Anything else?

This depends on SPIRV 1.1.

Locate the translator handling for `@llvm.global_ctors` and `@llvm.global_dtors`, then review how kernel functions receive execution modes. Confirm the implementation targets SPIR-V 1.1 and that constructors use `Initializer` while destructors use `Finalizer`; add or run coverage for both cases if the project provides it.

Written by the indexing model from the issue text.