Empty the current line if it's entirely inside a comment.
Don't incorrectly end a block comment at the second line if it doesn't
contain `*/`.
Recognize `/*` to start a multiline comment even if it isn't at the start of
the line.
When stripping off comments, consistently strip off `/*` and `*/`.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>