Integrate perlio:

[ 14526]
Fix SvGROW on an SV with SvLEN == 0 - copy in any existing data.
(Mis-feature discovered by Encode.)

[ 14518]
indent -kr -nce and some manual tweaks to match perl style.

p4raw-link: @14526 on //depot/perlio: 4056517955bef99f1d248dcaf966c0e256b0ea31
p4raw-link: @14518 on //depot/perlio: aa0053b7f4fe5f775a26681d0e18999f5a01d34c

p4raw-id: //depot/perl@14531