Take padding and margin of the creatable actions div into account

There are some differences in width handling between the browsers used
to run the tests, most likely due to their support (or lack of) of
certain CSS features: PhantomJS requires "width" to be set (probably
because it does not handle flex displays and treats it like a block, so
"min-width" does not matter in this case), while Firefox requires
"min-width" to be set (otherwise the children of "#controls" could be
compressed due to its use of flex display and the elements would end
with a different width than the one needed for the tests). Due to all
that the width of the breadcrumb siblings must be specified in the tests
using both "width" and "min-width".

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>