* update docs for `@byteSwap`.
* fix hash & eql functions for ZigLLVMFnIdBswap not updated to
include vector len. this was causing incorrect bswap function
being called in unrelated code
* fix `@byteSwap` behavior tests only testing comptime and not
runtime operations
* implement runtime `@byteSwap`
* fix incorrect logic in ir_render_vector_to_array and
ir_render_array_to_vector with regards to whether or not to bitcast
* `@byteSwap` accepts an array operand which it will cast to vector
* simplify `@byteSwap` semantic analysis code and various fixes
380c8ec2c9