Backtraces print byte code instead of original expression for byte compiled tests

[snogge]

First reported in #218 (comment) .

For expect forms like

(expect (+ 1 2) :to-equal 2)

both (+ 1 2) and 2 are stored in non-expanded form so they can be printed in the report in case the test fails. The trick used to do this does not work for byte compiled tests.

Two solutions that might work are

• use more trickery in expect and save the original expression in the docstrings of the lambda functions.
• stop using trickery in expect and use proper objects/structs instead.

[alphapapa]

I'd vote for solution 2, but I can't offer to help implement it, so... :)