Fixed more ternary concatenation bugs

[mbien]

inspired by #9459

I ran:

"possible bug: ambiguous ternary concatenation":
$pre + $nullable != null ? $a : $b =>
$pre + ($nullable != null ? $a : $b)
;;

"possible bug: ambiguous ternary concatenation":
$pre + $nullable == null ? $a : $b =>
$pre + ($nullable == null ? $a : $b)
;;

Eval order is from left to right which can lead to undesired effects when the right side has a ternary operator.

This puts the ternary operation in braces (or avoids the situation by other means)

[tmysik]

Looks good to me, thank you