[llvm] Update callers of isTriviallyReMaterializable to check trivialness (PR #160319)

[Philip Reames via llvm-commits]

preames wrote:

Noting I've seen the two failures reported by CI, and believe them to be real.  This bot is testing an off by default configuration I can't reproduce locally, so I'm going to have to do a speculative fix.  Running out in a moment for an errand, but will try to get these fixed a bit later today.  

https://github.com/llvm/llvm-project/pull/160319