`conditional_to_if` idempotence failure with very short margin

[penelopeysm]

s = "p ? (q; r) : s"

test_format(s, nothing; margin=4, conditional_to_if=true)

Formatting was not idempotent.

First pass:
if p
    (
    q;
    r
)
else
    s
end

Second pass:
if p
    (
        q;
        r
    )
else
    s
end

If the margin is large enough to fit (q; r) on one line, this isn't a problem. It's specifically an issue with the way (q; r) is nested.

Personally, I'm really not very inclined to fix this because conditional_to_if is known to cause idempotence failures anyway, plus the trigger is quite specific. If someone complains, I'll fix it, but otherwise, mehhh.

[penelopeysm]

Ordinarily idempotence failures would be P4, but downgrading this because of the above.