Improve error message for macro argument mismatch

[mlubin]

julia> macro m(x)
       x
       end

julia> @m(1,2)
ERROR: wrong number of arguments

It would be great to include the corresponding macro name in the error message. I traced the message to codegen.cpp, but I'm not familiar enough with the code to easily make this change.

[mlubin]

Any hope for fixing this? Our only workaround in JuMP is to make all macros varargs, which is nasty.

[ihnorton]

Leaving someone (possibly future-me) some breadcrumbs here:

• corresponding macro name in the error message could be solved by appending the macro name to the ErrorException error message in the catch block in fl_invoke_julia_macro. I'm not really sure how to do that safely though, because the message is not guaranteed to be an ASCIIString.
• also noting that we already emit debug info just fine (look at gdblookup for frame 2 after breaking in jl_throw with the example above). the problem is that we don't generate the backtrace right away because we have to return through flisp before actually throwing.

[JeffBezanson]

Fixed by #14563.