This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
I often run llvm-reduce on IR that contains debug info, this prevents an
extra step of `opt -passes=strip` I do every time and will result in a
lot less invalid reductions around debug metadata.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D136208