Eliminate PL_sawalias, GPf_ALIASED_SV

These two commits:

    v5.21.3-759-gff2a62e "Skip no-common-vars optimisation for aliases"
    v5.21.4-210-gc997e36 "Make list assignment respect foreach aliasing"

added a run-time mechanism to detect aliased package variables,
by either "*pkg = ...," or "for $pkg (...)", and used that information
to enable the OPpASSIGN_COMMON mechanism at runtime for detecting common
elements in a list assign, e.g.

    for $alias ($a, ...) {
        ($a,$b) = (1,$alias);
    }

The previous commit but one changed the OPpASSIGN_COMMON mechanism such
that it no longer uses PL_sawalias. So this var and the mechanism for
setting it can now be removed.

This commit removes:

    * the PL_sawalias variable
    * the GPf_ALIASED_SV GP flag
    * the SAVEt_GP_ALIASED_SV and save_aliased_sv() save type.

1 files changed, 0 insertions, 1 deletions

diff --git a/pp_ctl.c b/pp_ctl.c
index cc6a55f76e..5b58f47684 100644
--- a/pp_ctl.c
+++ b/pp_ctl.c
@@ -2145,7 +2145,6 @@ PP(pp_enteriter)
 	save_pushptrptr(gv, SvREFCNT_inc(*svp), SAVEt_GVSV);
 	*svp = newSV(0);
 	itervar = (void *)gv;
-	save_aliased_sv(gv);
     }
     else {
 	SV * const sv = POPs;