[cfe] Wrong class name for record with one positional field

[sgrekhov]

(2,) + (3,); // Error: The operator '+' isn't defined for the class '(int)'.

The error message in CFE looks as if the + operator is not defined for the int class. Please change the class name to (int,), as it is done in the analyzer.

Dart SDK version: 3.8.0-166.0.dev (dev) (Tue Mar 4 20:02:17 2025 -0800) on "windows_x64"

[lrhn]

(And consider not using the word "class" about a record type. That's confusing too. Maybe just use "type" instead in general.)