Show evaluated test arguments from broadcast functions

[omus]

While working on #57825 I noticed that broadcasted functions were not we'll supported by the @test macro and never showed the evaluated test arguments. I've updated the stdlib to support this which required some large enough refactoring that it seemed best to make a separate PR for this change. The changes include:

• Avoid embedding function references into Expr. This made the code harder to reason aboue than it needed to be.
• Breaking up eval_test into eval_test_comparison and eval_test_function due to changes to the functions arguments
• Handle broadcast syntax for binary operators (e.g. 1 .== 1 and function calls (==).(1, 1))
• Create new _escaped_call function which abstracts escaping all of the arguments for a function call. Doing this made it handling the special call syntax for broadcasting easier.
• Perform a single pass on function arguments when escaping where previously we did two passes.

Depends on:

• Show evaluated test arguments for functions with 1 & 2 arguments #57825

[vtjnash]

SGTM