gas: drop .appfile and .appline

gas: drop .appfile and .appline

These were used originally to represent "# <line> <file>" constructs
inserted by (typically) compilers when pre-processing. Quite some time
ago they were replaced by .linefile though. Since the original
directives were never documented, we ought to be able to remove support
for them. As a result in a number of case function parameter aren't used
anymore and can hence be dropped.