Remove redundant comments

[Rangi42]

Many comments are just restating what's obvious from modern label and constant names (although they were more relevant when the disassembly was still in progress and things were unidentified). Some regexes that help find many instances of them:

• git grep -P '^\t(ld [abcdehl],|call( n?[zc],)?|j[pr]( n?[zc],)?|cp) [A-Z][A-Za-z0-9_]+ ; '
• git grep -P '^\tldh? a, \[[whv][A-Z].+\] ; '
• git grep -P '^\t(bit|res|set) [A-Z][A-Za-z0-9_]+, \S+ ; '

(Those turn up hundreds of lines, and many of them are false positives, useful comments that we should keep or maybe reword or occasionally turn into ASSERTs.)

[dannye]

lol this is a dupe of #302