fix: Fix 3 parser test cases in parsing

[yordanmadzhunkov]

Description

Fixed some test code in parser. The biggest change is

• parse_all_failing test function is now satisfied by errors only ( previous version treated warning as errors )
• Fix 3 parser test cases from failing to passing
• Fix typo in is_warning

Problem*

Prior to this PR this test cases triggered errors by in the parser

trait GenericTrait<T> { fn elem(&mut self, index: Field) -> T; }

trait GenericTraitWithConstraints<T> where T: SomeTrait { fn elem(self, index: Field) -> T; }

trait TraitWithMultipleGenericParams<A, B, C> where A: SomeTrait, B: AnotherTrait<C> { let Size: Field; fn zero() -> Self; }

Resolves

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[yordanmadzhunkov]

@jfecher