3001

I basically need both checks. But why?
I need to relearn the lesson of 2502 from nearly six months ago :(

I'm also *really* feeling the slowness now. make+tests now takes nearly
7 minutes, and even make+repl takes nearly 2 minutes. How did I not
notice for the past week?
3002

Basically, read_all needs to keep going until there's no at_start_of_line
state to track. But that's true on either side of the newline, and it's
simpler for other passes to be indisciplined about consuming the
newline.

Indeed, it's easier to always leave the newline, than it is to always
consume it. What if there's multiple exprs on a line? No intervening
token to consume then. And putback is non-trivial to build for
indent_sensitive_stream.

Incidentally, tracing tokenize to screen shows a huge lag before it
prints the result. Is that part of the reason for the slowdown?
3003 - undo 3002

Agh, but there's another bug even back in 2502: lines starting with '(' and
ending in whitespace wait for another expr before printing.

Agh, this is horseshit. Bring back manual tests.
3004 - bring back manual tests

No other failures besides the initial-paren-and-trailing-comment-or-whitespace
ones we already know about.