[Support] Introduce createStringError helper function

The function in question is copy-pasted lots of times in DWARF-related classes.
Thus it will make sense to place its implementation into the Support library.

Reviewed by: lhames

Differential Revision: https://reviews.llvm.org/D49824



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337995 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed