[GlobalISel] Get rid of the ifdefs in TargetLowering.
Introduce a new API used only by GlobalISel: CallLowering.
This API will contain target hooks dedicated to call lowering.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260922 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed