Revert "fix #127855, in Perl_sv_setpvn() we have to overallocate to enable COW"

This reverts commit e19cb11142087974d956f263d24e146b968025d5.

This and the previous commit revert the two commits that were an original
fix for RT #127855, but which is fixed in a different way in a following
commit.  See the ticket for more details.

1 files changed, 1 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 68df702b56..0200679087 100644
--- a/sv.c
+++ b/sv.c
@@ -4891,7 +4891,7 @@ Perl_sv_setpvn(pTHX_ SV *const sv, const char *const ptr, const STRLEN len)
     }
     SvUPGRADE(sv, SVt_PV);
 
-    dptr = SvGROW(sv, len + 2);
+    dptr = SvGROW(sv, len + 1);
     Move(ptr,dptr,len,char);
     dptr[len] = '\0';
     SvCUR_set(sv, len);