lowering: Handle malformed `...` expressions (#57480)
Fixes #51572. The expander had a looser definition of a vararg than the
recursive logic destructing the vararg, so a bad expression like `(call
f (... x y))` could cause a stack overflow via indestructible mutant
semi-vararg.
This change produces a saner error in this situation:
```
julia> macro foo(); Expr(:(...), 1, 2, 3); end; (@foo,)
ERROR: syntax: wrong number of expressions following "..." around REPL[1]:1
Stacktrace:
[1] top-level scope
@ REPL[1]:1
```
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Co-authored-by: Jameson Nash <vtjnash@gmail.com>
