[CS2] Lexer/Nodes: Expansion that becomes rest parameter causes runtime error

[Inve1951]

copy pasting from actual code

header = header[(6 + header.lastIndexOf "/\/ME"+"TA") ... header.lastIndexOf "*/\/"]  # BD EOL bug workaround

used to compile to: (cs2-beta3)

header = header.slice(6 + header.lastIndexOf("/\/ME" + "TA"), header.lastIndexOf("*/\/"));

output with beta4:

header = header[(6 + header.lastIndexOf("/\/ME" + "TA"))(...header.lastIndexOf("*/\/"))];

now throws at runtime: TypeError: (var)[Symbol.iterator] is not a function(…)
also the supposed comment is missing in the js

[GeoffreyBooth]

@zdenko do you mind taking a look at this?

[zdenko]

@GeoffreyBooth sure.

[GeoffreyBooth]

Fixed by #4634.