Reduce difference between files (#1155)

Moves `if (!gSkipCorrectnessTesting)` in binary_i.cpp to follow
structure of binary.cpp, unary.cpp, macro_unary.cpp and
macro_binary.cpp.

Other non-semantic changes include adding/removing new lines and
updating comments.

Signed-off-by: Marco Antognini <marco.antognini@arm.com>