[llvm] [offload] add handling of memory alignment to MemoryManagerTy (PR #218418)

[Jan Trusiłło via llvm-commits]

================

----------------
311Volt wrote:

It would work but I still suggest to not mutate `Size` and save the new size in another variable.

My point is, `const int B = findBucket(AllocSize);` would have made the initial bug more visible

https://github.com/llvm/llvm-project/pull/218418