For each R_Group diagnostic produced, this patch gives more
information about it by printing the absolute file path,
the line and column number the pass was applied to and finally
the remark option that was used.
Clang does the same with the exception of printing the relative
path rather than absolute path.
Depends on D159260. That patch adds support for backend passes
while this patch adds remark options to the backend test cases.
Reviewed By: awarzynski
Differential Revision: https://reviews.llvm.org/D159258
12da8ef0e3