Refactor(decomposition): Use of bitwise '&' with boolean operands

[wjrforcyber]

In decomposition.hpp, there's a bit operator & in condition which causes warning:

kitty/include/kitty/decomposition.hpp

Line 597 in 5b7ea89

if ( ( x_xor.first.size() != 0 ) & ( x_xor.second.size() != 0 ) )

warning: use of bitwise '&' with boolean operands [-Wbitwise-instead-of-logical]

So actually there won't be any error occur here but a condition short circuit will be missing if the first condition is false.

[HappyCat2]

已收到您的邮件，我将尽快给您回复。