Debug Info: In DIBuilder, the context fields of a TAG_inheritance and a
TAG_friend are updated to use scope reference.

Added testing cases to verify that class with inheritance can be uniqued.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190364 91177308-0d34-0410-b5e6-96231b3b80d8
Use a default value for the prologue's debug location.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190366 91177308-0d34-0410-b5e6-96231b3b80d8
Enable -misched-cyclicpath by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190367 91177308-0d34-0410-b5e6-96231b3b80d8