Fix bounded_int_trim libfunc (#1472)

* Test trim with u8 and i8

* Test trim with positive bounded ints

* Test trim with negative bounded ints

* Test trim with positive and negative bounded ints

* Add test for truncating value to target integer

* Make implementation simpler

* Use test_case

* Improve test utilities

* Replace match with if

* Simplify test by comparing output, instead of extracting inner values from output and comparing those

* Document panic_byte_array

Author: JulianGCalderon