Fix parser stuck in an error loop

[cdemirer]

Fixes (4.0) #53345

Using the repro from this comment #53345 (comment) because I couldn't reproduce it with the code in the initial comment.

When lambda functions were added to GDScript, the behavior of parse_precedence had to be changed to not consume a token if a valid prefix rule didn't exist.

godot/modules/gdscript/gdscript_parser.cpp

Line 2140 in d26442e

advance(); // Only consume the token if there's a valid rule.

However, this can cause the parser to be stuck in an infinite loop in certain cases, since it never consumes the token causing the error.

With the assumption that this only happens with expression statements, I added an advance() call there, which will be called alongside the parser error.

Bugsquad edit: This closes #53345.

[vnen]

Thanks!