[llvm] [CodeGen][MISched] Handle empty sized resource usage. (PR #75951)

[Michael Maitland via llvm-commits]

michaelmaitland wrote:

> A ResourceSegment is always created, even with your changes, it is just that you keep it empty (no intervals in it).

You are right that a ResourceSegment is always created, even with my changes, but it has no interval in it. I will reword the commit message accordingly.

https://github.com/llvm/llvm-project/pull/75951