[llvm] [offload][SYCL] Add SYCL Module splitting. (PR #131347)

[Maksim Sabianin via llvm-commits]

maksimsab wrote:

> If you have seen the string, use the old integer, otherwise the number of strings you've seen so far.

This would lead to complications for users, forcing them to come up with stateful functors in order to maintain previously seen functions.

Additionally, it would complicate testing since we currently depend on the sorted order provided by the `std::map<std::string, ...>`. With your approach, the order will depend on the order of the functions in the module.

https://github.com/llvm/llvm-project/pull/131347