[llvm] [Inliner] Add option (default off) to inline all calls regardless of the cost (PR #152365)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> LGTM.
> 
> @arsenm @yxsamliu I vaguely recall that AMDGPU builds sometimes wanted to inline everything. Perhaps this could be a useful knob which could be used for that purpose while leaving normal inlining heuristics in place for the rest of the builds.

We have AMDGPUAlwaysInlinePass already (which I want to delete without replacement) 

https://github.com/llvm/llvm-project/pull/152365