Finish cleaning up whitespace differences.

Finish cleaning up whitespace differences.

The last remaining thing here was that when a line ended with a macro,
and the parser looked ahead to the newline token, the lexer was
printing that newline before the parser printed the expansion of the
macro.

The fix is simple, just make the lexer tell the parser that a newline
is needed, and the parser can wait until reducing a production to
print that newline.

With this, we now pass the entire test suite with simply "diff -u", so
we no longer have any diff options hiding whitespace bugs from
us. Hurrah!