LLVMTargetMachine: Add functions to create MIModuleInfo/MIFunction; NFC

Add convenience function to create MachineModuleInfo and
MachineFunctionAnalysis passes and add them to a pass manager.

Despite factoring out some shared code in
LiveIntervalTest/LLVMTargetMachine this will be used by my upcoming llc
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269002 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed