Fix bug #16179 with ls-lisp emulation of the ls -s switch.

Fix bug #16179 with ls-lisp emulation of the ls -s switch.

 src/ls-lisp.el (ls-lisp-insert-directory): Don't modify %d and %f
 formats for displaying file sizes when the -s switch is given.
 Instead, compute a separate format for displaying the size in
 blocks, which is displayed in addition to the "regular" size.
 When -h is given in addition to -s, produce size in blocks in
 human-readable form as well.