Rm Perl_sv_utf8_upgrade() from mathoms

This function can be converted to call plain sv_utf8_upgrade  without
changing its behavior.  I verified this by eyeballing its implementation
in mathoms.c and comparing that with what happens with just the plain
macro.

That means embed.fnc can be changed to generate the Perl_ form
automatically, and the mathoms function can be removed.

Author: khwilliamson

embed.fnc

@@ -3532,7 +3532,7 @@ Adm	|bool	|sv_utf8_downgrade_nomg 				\
 				|NN SV * const sv			\
 				|const bool fail_ok
 Adp	|void	|sv_utf8_encode |NN SV * const sv
-AMbdp	|STRLEN |sv_utf8_upgrade|NN SV *sv
+Admp	|STRLEN |sv_utf8_upgrade|NN SV *sv
 Adm	|STRLEN |sv_utf8_upgrade_flags					\
 				|NN SV * const sv			\
 				|const I32 flags

embed.h

@@ -2325,6 +2325,7 @@
 #   define Perl_sv_usepvn(mTHX,a,b,c)           sv_usepvn(a,b,c)
 #   define Perl_sv_usepvn_mg(mTHX,a,b,c)        sv_usepvn_mg(a,b,c)
 #   define Perl_sv_utf8_downgrade(mTHX,a,b)     sv_utf8_downgrade(a,b)
+#   define Perl_sv_utf8_upgrade(mTHX,a)         sv_utf8_upgrade(a)
 #   define Perl_uv_to_utf8_msgs(mTHX,a,b,c,d)   uv_to_utf8_msgs(a,b,c,d)
 #   define thread_locale_init()                 Perl_thread_locale_init(aTHX)
 #   define thread_locale_term()                 Perl_thread_locale_term(aTHX)
@@ -2384,6 +2385,7 @@
 #   define Perl_sv_usepvn                       sv_usepvn
 #   define Perl_sv_usepvn_mg                    sv_usepvn_mg
 #   define Perl_sv_utf8_downgrade               sv_utf8_downgrade
+#   define Perl_sv_utf8_upgrade                 sv_utf8_upgrade
 #   define Perl_uv_to_utf8_msgs                 uv_to_utf8_msgs
 #   if defined(PERL_DONT_CREATE_GVSV)
 #     define Perl_gv_SVadd                      gv_SVadd

mathoms.c

@@ -128,18 +128,6 @@ Perl_sv_pvutf8(pTHX_ SV *sv)
     return sv_pv(sv);
 }
 
-/* sv_utf8_upgrade() is now a macro using sv_utf8_upgrade_flags();
- * this function provided for binary compatibility only
- */
-
-STRLEN
-Perl_sv_utf8_upgrade(pTHX_ SV *sv)
-{
-    PERL_ARGS_ASSERT_SV_UTF8_UPGRADE;
-
-    return sv_utf8_upgrade(sv);
-}
-
 #if defined(HUGE_VAL) || (defined(USE_LONG_DOUBLE) && defined(HUGE_VALL))
 /*
  * This hack is to force load of "huge" support from libm.a