A number of the --debug-* options in llvm-dwarfdump are not particularly well tested. In some cases, the option is only tested as part of testing another feature, or a specific part of the section that the options dump. This change adds four new tests to address some of these holes. It is not aiming to address every hole however.
I kept the --debug-line switch test separate to X86/brief.s because the latter only considers the parts of the line table that are affected by verbose printing, thus missing out things like the header and different values for things like the Line, Column etc registers.
Depends on D71274.