Fix incorrect implementation of fail function

[Anon-im]

Description

In the current implementation, the fail function calls itself without a termination condition, leading to infinite recursion. Instead of invoking the fail function from the parent DSTest contract, the current implementation loops on itself, making it impossible to properly execute tests and handle errors.

Problem*

Resolves

Summary*

Additional Context

PR Checklist*

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

[Anon-im]

@critesjosh Transfered PR to the foundry repo as requested! Thanks!